Current Affairs 8th Class

Main Directions: There are four main directions viz. East, West, North and South. East and West as well as North and South are opposite to each other as shown below. The sun always rises in the East and sets in the West.   Four Other Directions: There are four other directions which lie in between the four main directions. These are: North-East (N-E), North-West (N-W), South-East (S-E), South-West (S-W)     Two Cyclic Directions: There are two cyclic directions namely clockwise and anticlockwise. The direction in which the hands of a clock move is called clockwise direction while its opposite direction is called anticlockwise direction as shown below.       EXAMPLE   Priya goes 12 km towards North from a fixed point and then she goes 8 km towards South from there. In the end she goes 3 km towards East. How far and in which direction is she from her starting point? (a) 5 km, North-East        (b) 5 km. West      (c) 7 km, West                   (d) 7 km. East   Explanation (a): Let Priya starts from the point P and reach Q.   Then from Q, she returns to R. At the end she goes from R to S. Clearly, Priya is finally at S. S is in North-East of P. In APRS, ZPRS =           Using Pythagoras theorem, we get Thus Priya is 5 km away from the initial point in North-East of the initial point. So the correct option is (a).

WHAT IS VENN DIAGRAM? Venn diagram is a pictorial representation of classes representing items and their common properties. We usually use circles to draw a venn diagram. A venn diagram consists of two or more circles. Circles may or may not have some common regions according as the respective classes have or do not have common properties amongst them. Let us illustrate venn diagrams with the following example.     EXAMPLE   1.         Which of the following figures represents the relation between 'Gases', 'Liquids' and 'Solids'?                                                                                      (a)                     (b)               (c)                 (d)   Explanation (d): Gas, liquid and solid all the three are different states of a substance. Therefore the desired Venn diagram is:    So, the correct option is (d).   2.         In the following diagram, the square represents women, triangle represents corporate managers and circle represents MBAs. Which numbered part represents MBA corporate managers who are women?                     (a) 6                              (b) 5                        (c) 4                              (d) 10                 Explanation (a): MBA corporate managers who are women are represented by the common region to circle, triangle and square, which is 6. So, the correct option is (a).

  ALPHA-NUMERIC SEQUENCE PUZZLE   In such type of questions, a sequence of numbers, letters and symbols is given and a student i5 asked how many times a number/letter/symbol follows a certain rule or which number/letter symbol follows a certain rule.     EXAMPLE   1.  How many symbols are there in the given arrangement each of which is not immediately preceded by a digit but immediately followed by a letter?        4 2 @ + A P 5 > - 6 < T M 4 L Z = 1 - 8 3 D * #       (a) None                        (b) One                  (d) Two                         (d) Three   Explanation (b): The group having given properties is @ + A. So, the correct option is (B).     NUMBER, RANKING AND TIME SEQUENCE TEST   Number Test: In these type of problems, a sequence of numbers is given and a student is asked questions same as in the way as asked in Alpha-Numeric Sequence Puzzle. Ranking Test: In ranking test based problems, usually the ranks of one or two persons from the top and from the bottom are mentioned. A student is required to compute either total number of persons or rank of a person.   2.  In a class of 60, the girls are twice that of boys, Karim ranked seventeenth from the top. If there are 9 girls ahead of Karim, how many boys are there after him?       (a) 3                              (b) 10                   (d) 12                            (d) 15   Explanation (c): Let number of boys = x, then x + 2x = 60 x = 20 There are 16-9=7 boys ahead of Karim. ' Number of boys after Karim =20-1 -7=12   Time Sequence Test: To solve the time based problems the following information are very useful.

•          The needles of a clock are called its hands.
•          Whenever we are performing problems on two hands of a clock, they are hour and minute hands.
•          In every 1 hour, the hour hand rotates 30° and the minute hand rotates 360°.
•          The month of February more...

There are four fundamental operations. These are addition (+), subtraction (-), multiplication (x) and division. Whenever two or more of these operations occur simultaneously, we overcome on such complex situation by applying the 'B 0 D M A S' rule. This chapter is on the basis of the 'B 0 D M A S' rule. Let us explain this rule briefly. We solve an expression first for 'bracket'(if available), then for of (if available). This process goes up to subtraction.     EXAMPLE   Which one of the four interchanges in signs and numbers would make the equation  true? (a) 2 and 3,  and      (b) 6 and 2, and (c) 3 and 6, and =       (d) 3 and 6,  and   Explanation (d): By applying given interchanges, we get option (d) which satisfies the equation.  becomes which is true. So the correct option is (d).  

In this chapter, problems are based upon number of lines, triangles, quadrilaterals etc. ·         To count number of lines, add all number of the horizontal, vertical and slanting lines. ·         To count the number of triangles, add all the number of triangles made up of 1 component, 2 components, 3 components and so on. ·         The same process is for counting the number of other polygons.     Special Case: Suppose a large square is divided into some small equal squares. If each side of the big square is sticking 'n' small squares, then the number of all possible squares is obtained by the following formula. Number of squares = \[{{n}^{2}}+\,\,{{\left( n\text{ }-\text{ }1 \right)}^{2}}+\,\,{{\left( n\text{ }-\text{ }2 \right)}^{2}}+........+\text{ }{{2}^{2}}+\text{ }{{1}^{2}}\]   Note: Number of all squares on a chessboard = 204.   Fig.: Chessboard     EXAMPLE   Count the number of parallelograms in the given figure.   (a) 15                            (b) 12    (c) 10                            (d) 9   Explanation (a): The figure may be labelled as shown in the adjoining figure.   The parallelograms composed of one component each are LMHJ and BDFM i.e., 2 in number. The parallelograms composed of two components each are ABML and HGFM i.e., 2 in number. The parallelograms composed of three components each are LBHI, LBEF, BDGH, DFLA, BCFH, KLFH, ABHJ and LFGJ i.e., 8 in number. The parallelograms composed of six components each are LCFI, KBEH and ADGJ i.e., 3 in number. \[\therefore \]Total number of parallelograms =2+2+8+3=15. So the correct option is (a).  

MIRROR IMAGES   Suppose someone stands in front of a plane mirror. If he lifts his left hand, the image in the mirror will lift his right hand and vice-versa. The left half of a body becomes right half of its mirror image and right half becomes left half. Note: If not mentioned, the mirror is assumed to be placed vertically right of the object.     EXAMPLE   1. Choose the correct mirror image of the figure (X).                            (a)                   (b)         (c)                  (d)     Explanation (c): The black circle in the left side of the diagonal in the given image will reach right side of the diagonal in the mirror image.                                             WATER IMAGES   The water image of an object is the vertically inverted (upside down) of the object. The position of the water layer is horizontally just below the object.   2.  Choose the correct water image of the given combination of letters and digits.       P Q 8 A F 5 B Z 9      (a)       (b)        (c)        (d)     Explanation (a):

  EMBEDDED FIGURES   In this section, usually two types of problems are asked. Let us explain them briefly.

•          A simple figure (X) is provided. This figure (X) is embedded in any one of the four option figures.
•          A figure (X) is provided. This figure (X) embeds any one of the four option figures. A candidate requires to identify such figures.

    EXAMPLE   1. You are given a figure (X) followed by four option figures (a), (b), (c) and (d) such that figure (X) is exactly embedded in one of them. Trace out the option figure which contains figure (X) as its part.                   (a)                  (b)   (c)                  (d)    Explanation (c):  Option (c) exactly embeds the given figure (X) as its part.                   So the correct option is (c).     FIGURE FORMATION   This section deals with the following types of problems:                   I.           Formation of a Figure from its Segments: In such type of problems, all the parts that are required to form a figure are given. A candidate requires to identify the figure so formed out of the four options.                       II.       Choosing a Pattern which has the same components as a given Pattern : In such type of problems, a pattern of several components is given. A pattern out of four options contains the same components. A candidate requires to choose such pattern.                     III.         Rotation of a Figure: In such type of problems, a figure is given. A figure out of four options is the same figure as the given one, but this is obtained after rotating the given figure. A candidate requires to identify such figure.     2.   Find out which of the figures (a), (b), (c) and (d) can be formed from the pieces given in figure (X).                            (a)                 (b)          (c) more...

  FOLDING A TRANSPARENT SHEET   In such type of problems a figure of transparent sheet carrying a design on it is given. There is a dotted line on this sheet. This sheet has to be folded along the dotted line. A student requires to identify a figure from given options that looks similar to the folded sheet.     EXAMPLE   1. A square transparent sheet X, with a design and a dotted line on it is given. Choose the correct figure from the four options which represents the sheet X after folding it along the dotted line.                                  (a)                  (b)                  (c)                   (d)     Explanation (c): Clearly, the right half of the sheet X is put on the left half. The combination of the design in left half and mirror image of the design in the right half will appears on the folded sheet.     CUTTING A FOLDED PAPER   In such type of problems a paper is folded twice or thrice. Then one or more pieces of it are cut. After this the paper is absolutely unfolded. In this situation the paper has many cuts or holes on it. So it contains a pattern.   A student is required to identify a figure from given four options, that shows the unfolded form of sheet. Usually, the paper sheet is folded along the dotted lines marked on it. And arrows show the directions of folds.   2.  There are three figures marked X, Y and Z. Figures X and Y show the two consecutive folds of a square sheet of paper. And figure Z shows the cuts on the folded paper.            (a)            (b)        (c)             (d)     Explanation (a): So, the correct option is (a).

Cuboid: Cuboid is a uniform solid which has 6 faces, 8 corners and 12 edges.     Cube: Cube is a cuboid which has 6 identical faces.   Dice: A dice is a cube whose each face bears points or numbers from 1 to 6.     EXAMPLE     Count the number of cubes in the following figure.                (a) 28                            (b) 32           (c) 36                            (d) 40   Explanation (a) : Number of cubes in the bottom layer = 5 Number of cubes in the next layer = 8. Number of cubes in the next layer = 9 Number of cubes in the topmost layer = 6 \[\therefore \] Total number of cubes =5+8+9+6= 28     2. Here two positions of a dice are shown. If there are four dots in the bottom, then how many dots will be on the top?             (a) 2                              (b) 3                    (c) 5                              (d) 6   Explanation (b) : A student requires here the number of points opposite four points. Four points are showing in both the positions of dice. So none of 1 point, 2 points, 5 points and 6 points is opposite to 4 points. Therefore the required number of points is 3. So the correct option is (b).   3.  A solid cube of each side 8 cm has been painted on all the faces. It is then cut into cubical blocks of each side 2 cm. How many cubes have only two faces painted?     (a) 4                              (b) 8                   (c) 24                            (d) 32   Explanation (c): Number of cubes each having only two faces painted are on each 12 edges. Therefore number of cubes having two faces painted is 24.     4.   The sheet of paper shown in the figure (X). Choose a box from the four options that is similar to the box that formed.         more...

  DOT SITUATION In such type of problems one or more dot(s) is (are) placed somewhere in the region enclosed in between geometrical figures such as triangle, square, rectangle, circle, etc. A candidate is required to identify one alternative figure which has the same region(s) as the region(s) marked by dot(s) in the given figure.     EXAMPLE     Select the figure from the four options that has the same conditions of the placement of the dots as in Fig. (X).                                  (a)                (b)                 (c)              (d)   Explanation (b): In Fig. (X), there are two dots and four geometrical figures - square, rectangle, circle and triangle. Out of the two dots: (i) One dot lies in the region common to the circle and the square only. (ii) One dot lies in the region common to all the four figures, i.e. square, rectangle, circle and triangle.                                                                          Now, out of the four alternatives, only figure (b) has two different types of regions as shown below.     So the correct answer is (b).