Question

If y varies directly as x, and y is 180 when x is n and y is n when x is 5, what is the value of n?

18

Answer 1

30

Explanation:

y varies directly with x, so:

y = kx

When x = n, y = 180.

180 = kn

When x = 5, y = n.

n = 5k

Solve for k in the first equation:

k = 180 / n

Substitute into the second equation:

n = 5 (180 / n)

n = 900 / n

n² = 900

n = 30