Question

The variable z is directly proportional to x. When x is 3, z has the value 48. What is the value of z when x = 7?

Answer 1

112

Explanation:

Given z is directly proportional to x then the equation relating them is

z = kx ← k is the constant of proportionality

To find k use the condition x = 3 when z = 48

k =
`(z)/(x)` =
`(48)/(3)` = 16, thus

z = 16x ← equation of proportionality

When x = 7, then

z = 16 × 7 = 112