Question

Suppose y varies as x and y = 21 when x = 8 find y when x = 16

Answer 1

y = 42

Explanation:

given y varies as x then

y = kx ← k is the constant of variation

to find k use the given condition y = 21 when x = 8

k =
`(y)/(x)` =
`(21)/(8)`, hence

y =
`(21x)/(8)`

when x = 8 then y =
`(21(16))/(8)` = 42