Question

P is inversely proportional to Q.

When P=100, Q=32
Calculate the value of Q when P is twice as big as Q.
Show your working please

Answer 1

`If\ P\ is\ inversely\ proportional\ to\ Q\ then:\\\\P* Q=constans\\\\P=100;\ Q=32\\\\100*32=3200\\\\P=2Q\\\\therefore\\\\P* Q=2Q* Q=2Q^2\\\\2Q^2=3200\ \ \ \ |divide\ both\ sides\ by\ 2\\Q^2=1600\ \ \ \ \ |sqare\ rot\ both\ sides\\Q=√(1600)\\\boxed{Q=40}`