Question

If y varies inversely as x, and y = 18 when x = 2, find y when x = 4.
Answer

9/4

9

36

144
is the answer 36

Answer 1

ok, now y is inverse. proportional to x. now when y = 18, x = 2

You can use the unitary method.

If y = 18 then x = 2

If y = ? then x = 4

x turns out to be 36 but THAT IS WRONG. since if x increases then y decreases.

So y = 18x2/4 = 9

Hence y = 9.