Question

If z is directly proprotional to x and z = 12 when x = 3, find the value of x when z = 18

Answer 1

• 4.5

Explanation:

z is directly proportional to x

• z = kx, where k is coefficient

If z = 12 when x = 3

Then we have

• 12 = 3k
• k = 4

So the coefficient is 4

When z = 18, we have

• 18 = 4x
• x = 18/4
• x = 4.5