Question

Find the average (A) of four quantities p, q, r and s. If A = 6, p = 3, q = 5 and r = 7 ; find the value of s.

Answer 1

A = ( p + q + r + s ) / 4
6 = ( 3 + 5 + 7 + s )/4
6 * 4 = 3 + 5 + 7 + s
24 = 3 + 5 + 7 + s
24 = 15 +s
24 - 15 = s
9 = s
so the s is 9