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 =
totalageofallpersons
numberofpersons
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.