The average height of a starfruit tree, a persimmon tree and a chikoo tree is 11.6 m. The chikoo tree is four times as tall as the persimmon tree and 1.2 m taller than the starfruit tree. Find the average height of the starfruit tree and the persimmon tree.
Total height of the starfruit tree, the persimmon tree and the chikoo tree
= 3 x 11.6
= 34.8 m

Height of the persimmon tree = 1 u
Height of the chikoo tree = 4 u
Height of the starfruit tree = 4 u - 1.2

Total height of the starfruit tree, the persimmon tree and the chikoo tree
= 1 u + 4 u + 4 u - 1.2
= 9 u - 1.2

9 u - 1.2 = 34.8
9 u = 34.8 + 1.2
9 u = 36

1 u = 36 ÷ 9 = 4

Total height of the starfruit tree and the persimmon tree
= 1 u + 4 u - 1.2
= 5 u - 1.2
= 5 x 4 - 1.2
= 20 - 1.2
= 18.8 m

Average height of the starfruit tree and the persimmon tree
= 18.8 ÷ 2
= 9.4 m

Answer(s): 9.4 m