Question

The value of y is directly proportional to the value

of x. If x = 8, then y = 12. What is the value of x when y = 30?

Answer 1

If the value of y is directly proportional to the value of x, we can use the formula for direct variation to find the value of x when y = 30. The formula for direct variation is:

y = kx

where k is the constant of proportionality.

To find the value of k, we can use the values given in the problem:

y = kx

12 = k(8)

Solving for k, we get:

k = 12/8 = 3/2

Now that we know k, we can use the formula for direct variation to find the value of x when y = 30:

y = kx

30 = (3/2)x

Solving for x, we get:

x = (30)/(3/2) = 20

Therefore, when y = 30, x = 20