Given: The average height of 2 children is 1.3 meters. The average height of their parents(father and mother) is 1.7 meters. The height of grandfather is 1.6 meters. Formula Used: Average = sum of total terms/ total number of terms Calculation: The average height of 2 children is 1.3 meters. Average = sum of total terms/ total number of terms ⇒ 1.3 = sum of the height of 2 children / 2 ⇒ Sum of the height of 2 children = 2 × 1.3 ⇒ Sum of the height of 2 children = 2.6 meters The average height of their parents(father and mother) is 1.7 meters. Average = sum of total terms/ total number of terms ⇒ 1.7 = sum of the height of father and mother / 2 ⇒ Sum of the height of father and mother = 1.7 × 2 ⇒ Sum of the height of father and mother = 3.4 meters The height of grandfather is 1.6 meters. The average height of the whole family = sum of the height of all family members/ total number of family members. ⇒ The average height of the whole family = (2.6 + 3.4 + 1.6) / 5 ⇒ The average height of the whole family = 7.60 / 5 ⇒ The average height of the whole family = 1.52 meters ∴ The average height of the whole family is 1.52 meters