Question

Y is inversely proportional to x. When y=25, x=4 Work out y when x=20

Answer 1

y=5 when x=20

Explanation:

Using the format for inverse proportions: y=k/x

To find k, substitute 25 in for y and 4 for x to find:

25=k/4 ⇒ k=100

Using this we can substitute k and x in for 100 and 20 to find:

y=100/20 ⇒ y=5