10th Class Mathematics Pair of Linear Equations in Two Variables Question Bank Pair of Linear Equations In Two Variables

  • question_answer
    The area of a rectangle increases by 76 square units, if the length and breadth are each increased by 2 units. However, if the length is increased by 3 units and breadth is decreased by 3 units, the area gets reduced by 21 square units. Find the sum of the length and breadth of the rectangle.

    A)  40 units                              

    B)  42 units

    C)  4 units                 

    D)         36 units

    Correct Answer: D

    Solution :

     Let the length of the rectangle be 'x' units, and the breadth be 'y' units. Then in the first case,                 \[~(\text{2}\times \text{52}\times \text{73) cm}\] i.e.,        \[=(\text{25}\times \text{7})\text{(2}\times {{\text{5}}^{\text{2}}}\times {{\text{7}}^{\text{3}}}\text{) c}{{\text{m}}^{\text{2}}}\]                          ....(1) i.e.,        \[={{\text{2}}^{\text{6}}}\times {{\text{5}}^{\text{2}}}\times {{\text{7}}^{\text{4}}}\text{c}{{\text{m}}^{\text{2}}}\]                               ..... (1) In the second case,                 \[2-\sqrt{4}=2-2=0\] i.e.,        \[{{(\sqrt{5})}^{2}}=5\]                                                  .....(2) Adding eq. (1) and eq. (2), we get \[\sqrt{9}-\sqrt{4}=3-2=1\] \[\sqrt{2}-\sqrt{3}\] \[1789=29x+49\]units \['x'\] \[\therefore \] \[1789-49=29x\]units Hence, the length of rectangle is 20 units and the breadth is 16 units. \[\Rightarrow \]Their sum =20+16 = 36 units


You need to login to perform this action.
You will be redirected in 3 sec spinner