Question

Given that y and x are directly proportional and

y=2 when x=7, find the value of y when x=17.5.

Answer 1

y = 5.

Explanation:

Direct proportionality is : y = kx where k is a constant.

Finding k by substituting the given values of x and y:

2 = k * 7

k = 2/7.

So the equation is y = 2/7 x.

When x = 17.5:

y = 2/7 * 17.5

y = 5.

Answer 2

The answer is: 5.

Explanation:

Set up an equation:

2 / 7 = y / 17.5

Cross multiply:

7y = 2 * 17.5

7y = 35

y = 35 / 7 = 5