RRB Group-D Model Paper 16 with answers for online practice

Given:
The average of five numbers a, b, c, d and e = 17.2
The average of the numbers b, c and d is 15
a = 10
Formula:
Average of n numbers a1, a2, ..., an = (a1 + a2 + ... + an)/n
Calculation:
(a + b + c + d + e)/5 = 17.2
⇒ a + b + c + d + e = 5 × 17.2 = 86
(b + c + d)/3 = 15
⇒ b + c + d = 45
a = 10
a + b + c + d + e = 86
⇒ 10 + 45 + e = 86
e = 86 – 55 = 31