Solution:
Given:
The average monthly income of the father and mother is Rs. 5,000
The average monthly income of the mother and her son is Rs. 6,000
The average monthly income of the father and his son is Rs. 10,000
Formula used:
Average = Sum of numbers/numbers of units
Calculation
The monthly income of the father and mother = 2 × 5,000
= 10000
The monthly income of the mother and her son = 2 × 6,000
= 12000
The monthly income of the father and his son = 2 × 10,000
= 20000
The monthly income of the family = (10000 + 12000 + 20000)/2
= 21000
The monthly income (in Rs.) of the father = 21000 - 12000
= 9000
The answer is 9000.
