p, q, r, s, t are five numbers such that the average of p, q and
| p, q, r, s, t are five numbers such that the average of p, q and r is 5 and that of s and t is 10. What is the average of all the five numbers?
A. 7.75
B. 7.5
C. 7
D. 5
Please scroll down to see the correct answer and solution guide.
Right Answer is: C
SOLUTION
According to the question p + q + r = 5 3 = 15 ….. (i)
s + t = 10 
2 = 20 …… (ii)
from equations (i) and (ii), p + q + r + s + t = 15 + 20 = 35
Average p, q, r, s and t = 
= 7
