Question

If y varies inversely with x, and y is 8 when x is 5, find y when x is 2.

Answer 1

• y=1/x
• y=k/x
• k=yx
• given y=8, x=5
• k=8×5=40
• finding y when x=2
• y=40/2=20ans

Answer 2

y = 20

Explanation:

Given that y varies inversely with x then the equation relating them is

y =
`(k)/(x)` ← k is the constant of variation

To find k use the condition y = 8 when x = 5, then

k = yx = 8 × 5 = 40

y =
`(40)/(x)` ← equation of variation

When x = 2, then

y =
`(40)/(2)` = 20