Question

If x varies inversely as yand x=20 when y =600 , find y when x =400

Answer 1

if x and y are inversely proportional, k=xy
                                                            =20 X 600
                                                            =12000
then y =k/x
           =12000/400
           =30
ans: y=30

Answer 2

Given:

x varies inversely with y and x=20 when y =600.

To find:

We have to find the y when x is 400.

Solution:

To determine the value of y we have to follow the below steps as follows-

x varies inversely with y.

So, we can write-

$x = \frac{k}{y}$

Where k is the proportionality constant.

When x=20 when y =600.

So, the value of k is-

$20 = \frac{k}{600} \\ k = 12000$

Now the value of x is 400.

So, the value of y is as follows-

$400 = \frac{12000}{y} \\ y = 30$

The value of y is 30.