SSC MTS 5 Aug 2019 Shift 3 Paper

Tips & Tricks
Given:
Average age of mother and father = 28 years
Average age of mother, father and their child = 20 years
Formula used:
⇒ Average age = $\frac{\mathrm{total}\mathrm{age}\mathrm{of}\mathrm{all}\mathrm{persons}}{\mathrm{number}\mathrm{of}\mathrm{persons}}$
Calculation:
⇒ Total age of mother and father = 28 × 2 = 56 years ...(1)
⇒ Total age of mother, father and their child = 20 × 3 = 60 years ...(2)
From (1) and (2),
⇒ The age of child = 60 – 56 = 4 years
∴ The age of child is 4 years.