The average monthly income of the father and mother is ₹5,000. The average monthly income of the mother and her son is ₹6,000. The average monthly income of the father and his son is ₹10,000. Find the monthly income (in ₹) of the father.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 9000.
Let the age of father, mother, and son be F, M, and S
⇒ F + M = 5000 × 2 = ₹10000 .........(1
⇒ M + S = 6000 × 2 = ₹12000 .........(2
⇒ F + S = 10000 × 2 = ₹20000 ..........(3
Adding Equations 1, 2, and 3
⇒ F + M + S = (10000 + 12000 + 20000)/2 = 42000/2 = ₹21000
Subtracting Equation 2 From this
⇒ F = 21000 - 12000 = ₹9000