Correct Answer - Option 3 : 10
Given: The average pocket money of 3 friends A, B and C is 80 in a particular month. B spends double and C spends triple of what A spends during that month and the average of their unspent pocket money is 60.
Formula: Average of n numbers a1, a2, .…. an = (a1 + a2 + ... + an)/n
Calculation:
Total pocket money of (A + B + C) = 80 × 3 = 240
Total unspent pocket money = 60 × 3 = 180
Total spent money = 240 – 180 = 60
Let A spends Rs. x then B = 2x, and C = 3x
According to question
6x = 60
⇒ x = 10
∴ A spends Rs. 10.
