Question

Y is inversely proportional to x.
When y = 7, x= 9
Work out the value of y when x = 21.

Answer 1

y = 3

Explanation:

y is inversely proportional to x setup: y = k/x

'k' is the constant of variation; find this first

7 = k/9

k = 63

now use 'k' to find 'y'

y = 63/21

y = 3