Question

2. If a and b are inversely proportional,
then:
O(a) a + b = constant
O (b) a - b = constant
O (c) ab = constant
O (d) a/b = constant​

Answer 1

Answer:

ans is( a)

Step-by-step explanation:

I think it heip you

Answer 2

Answer:

Step-by-step explanation:



• Two quantities x and y are said to be in direct proportion if they

increase or decrease together in such a manner that the ratio of

their corresponding values remains constant. That is, x

y

= k where

k is a positive number, if x and y are in direct proportion or vary

directly. In case of direct proportion, if y1, y2 are the values of y

corresponding to the values x1, x2 of x respectively, then 1 2

1 2

x x

y y  .

• Two quantities x and y are said to be in inverse proportion if an

increase in x causes a proportional decrease in y and vice-versa, in

such a manner that the product of their corresponding values

remains constant. That is, xy = k where k is a positive number, if x

and y are in inverse proportion. In this case, if y1, y2 are the values

of y corresponding to the values x1, x2 of x respectively, then x1 y1=

x2 y2 or

x y

x y

1 1

2 2



• Quantities increasing or decreasing together need not always be

in direct proportion, same in the case of inverse proportion.

• When two quantities x and y are in direct proportion (or vary directly),

they are written as x ∝ y. Symbol “∝” stands for ‘is proportional to’.

12/04/18

 



• When two quantities x and y are in inverse proportion (or vary

inversely) they are written as x ∝ 1

y

.

  

In examples 1 to 3, there are four options out of which one is correct.

Choose the correct answer,

Example 1 : If x and y are directly proportional and when x = 13,

y = 39, which of the following is not a possible pair of

corresponding values of x and y ?

(a) 1 and 3 (b) 17 and 51

(c) 30 and 10 (d) 6 and 18

Solution : The correct answer is (c).

Example 2 : A car covers a distance in 40 minutes with an average

speed of 60 km per hour. The average speed to cover the

same distance in 30 minutes is

(a) 80 km/h (b)

45 km/h 2

(c) 70 km/h (d) 45 km/h

Solution : The correct answer is (a).

Example 3 : Which of the follow