# 8th Class Mathematics Direct and Inverse Proportions Question Bank

### done Direct and Inverse Proportions

• A) $\frac{1}{3}$

B) $\frac{3}{2}$

C) $6$

D) $\frac{1}{2}$

• A) 3

B) 4

C) 2

D) 6

• A) 4

B) 9

C) 12

D) 36

• A) 1.25

B) 1.5

C) 25

D) 2.25

• A) 4 and 9

B) 10 and 3.6

C) 72 and 0.5

D) 5 and 6

• A) Length of a side of square and its area vary directly with each other.

B) If one angle of a triangle is kept fixed then the measure of the remaining two angles vary inversely with each other.

C) The area of circle and its diameter vary directly with each other.

D) All of these

• A) 15 : 8

B) 12 ; 10

C) 8 : 5

D) 8 : 15

•  Column - I Column - II P. $x$ and $y$ are in direct proportion and $x=40$ when $y=120$. If $x=60$ then $y=$ (i) 160 Q. $x$ varies inversely as $y$ and $x=12$ when $y=300$, if $x=24$ then $y=$ (ii) 180 R. $x$ varies directly as $y$ and $y=50$ when $x=30$, if $x=96$ then $y=$ (iii) 130 S. $x$ varies inversely as $y$ and $y=650$ when $x=20$, if $x=100$ then $y=$ (iv) 150

A) P$\to$(iv); Q$\to$(i); R$\to$(iii); S$\to$(ii)

B) P$\to$(ii); Q$\to$(iv); R(i); S(iii)

C) P$\to$(iv); Q$\to$(i); R$\to$(iii); S$\to$(ii)

D) P$\to$(ii); Q$\to$(iv); R$\to$(i); S$\to$(iii)

• A) Direct proportion

B) Inverse proportion

C) Neither direct nor inverse proportion

D) None of these

• A) $\frac{x}{y}$ remains constant

B) $x-y$ remains constant

C) $x+y$ remains constant

D) $x\times y$ remains constant

• A) 12 days

B) 8 days

C) 7 days

D) 6 days

• A) Rs. 7.30

B) Rs. 7.00

C) Rs. 6.00

D) Rs. 6.30

• A) 18

B) 24

C) 30

D) 12

• A) 30

B) 35

C) 65

D) 45

• A) 40

B) 30

C) 50

D) 20

• A) 29

B) 35

C) 60

D) 40

• A) $2\times {{10}^{-4}}cm$

B) ${{10}^{3}}cm$

C) ${{10}^{-4}}cm$

D) ${{10}^{4}}\text{ }cm$

• A) 180

B) 200

C) 150

D) 100

• A) 20 minutes

B) 10 minutes

C) 15 minutes

D) 5 minutes

• A) 50

B) 40

C) 60

D) 100

•  (i) If x and y are in direct proportion, then (x-1) and (y-1) are also in direct proportion. (ii) If x and y are in inverse proportion then (x+2) and (y+2) are also in inverse proportion. (iii) Two quantities x and y are said to vary directly with each other if $\frac{x}{y}=k$, where k is a positive constant. (iv) When distance is kept fixed, then speed and time vary inversely with each other.

A)

 (i) (ii) (iii) (iv) T F F T

B)

 (i) (ii) (iii) (iv) T T F F

C)

 (i) (ii) (iii) (iv) F F T T

D)

 (i) (ii) (iii) (iv) T F T F

•  (i) The perimeter of circle and its diameter vary P with each other. (ii) if two quantities p and q vary inversely with each other then Q of their corresponding values remain constant. (iii) When x and y are in indirect proportion and if y doubles then x becomes R .

A)

 P Q R Inversely Ratio Double

B)

 P Q R Directly Product Half

C)

 P Q R Directly Product Half

D)

 P Q R Directly Product Half

•  Column - I Column - II (P) If the cost of 93m of a certain kind of plastic sheet is Rs. 1395, then what would it cost (in Rs.) to buy 105 m of such plastic sheet? (1) 42 (Q) 55 cows can graze a field in 16 days. How many cows will graze the same field in 10 days? (2) 18 (R) 18 men can reap a field in 35 days. For reaping the same field in 15 days; how many men are required? (3) 88 (S) Suneeta types 1080 words in one hour. What is her GWPM (gross words per minute)? (4) 1575

A)

 P Q R S 4 3 1 2

B)

 P Q R S 2 1 4 3

C)

 P Q R S 3 2 1 4

D)

 P Q R S 1 3 2 4

•  (i) What will he get in the month of June (in Rs,)? (ii) For how many days will he be working for Rs. 696?

A)

 (i) (ii) 1392 15

B)

 (i) (ii) 15 1392

C)

 (i) (ii) 1382 20

D)

 (i) (ii) 1392 20

•  (i) x 6 12 30 48 y 250 125 50 31.25 (ii) x 115 130 145 160 y 615 600 585 570 (iii) x 50 100 300 1200 y 300 150 100 75

A) Only (i)

B) Both (i) and (ii)

C) Both (ii) and (iii)

D) None of these