Question

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

Answer 1

Answer:

if y is inversely proportional to x

then y = k*1/x

or xy = k

x₁y₁ = x₂y₂ = x₃y₃ = k

therfore 9×7 = 21 × y₂

y₂ = (9×7)/21

=> 3

y = 3