Question

P is partly constant and partly varies as Q, when Q is 5, P is 20 and when Q is 8, P is 26. Find P when Q is 4.

Answer 1

p = mq+b
Using the two data points, you have
5m+b = 20
8m+b = 26
clearly, 3m=6, so now just finish it off

Answer 2

P is partly constant and partly varies as q when q is 5 p=20 and when q=8 p=26 find p when q=5