Question

The variable x varies directly as y . When y is 10 , x is 3/2 . Find y when x is 9.

Answer 1

60----------------------

Answer 2

Given:

• X is directly proportional to Y
• The value of Y when X is 3/2 = 10

To Find:

• The value of Y when x is 9.

Solution:

Since X∝Y, we can write

⇒ Y = KX  → {equation 1}

Where "K" is the proportionality constant.

We have the values of X and Y and by using this we should find the value of "K". On substituting the values in equation 1 we get,

⇒ 10 = K*(3/2)

⇒ K = (2/3)*10 {multiplying the terms}

⇒ K = 20/3

Now we have the value of K, let us find the value of Y when X is 9. On substituting the values of X and K in equation 1 we get,

⇒ Y = (20/3)*9 {cancelling the divisible terms}

⇒ Y = 20*3 = 60 {multiplying the terms}

∴ The value of Y when X is 9 = 60.