Question

Y varies directly as x , y= 25 when x=5. Determine y when x= 13

Answer 1

y = 65 when x = 13

Explanation:

Here we have a proportion problem.

Y varies directly as x means that y equals the product of x and a constant

Let’s say our constant is k

Thus;

y = kx

now, k = y/x

Using the initial values;

k = 25/5 = 5

Now we want to get y when x = 13

Recall; y = kx

Thus using the value of k earlier calculated;

y = 13 * 5

y = 65