The average height of a chikoo tree, a durian tree and a persimmon tree is 4.4 m. The persimmon tree is twice as tall as the durian tree and 1.8 m taller than the chikoo tree. Find the average height of the chikoo tree and the durian tree.
Total height of the chikoo tree, the durian tree and the persimmon tree
= 3 x 4.4
= 13.2 m

Height of the durian tree = 1 u
Height of the persimmon tree = 2 u
Height of the chikoo tree = 2 u - 1.8

Total height of the chikoo tree, the durian tree and the persimmon tree
= 1 u + 2 u + 2 u - 1.8
= 5 u - 1.8

5 u - 1.8 = 13.2
5 u = 13.2 + 1.8
5 u = 15

1 u = 15 ÷ 5 = 3

Total height of the chikoo tree and the durian tree
= 1 u + 2 u - 1.8
= 3 u - 1.8
= 3 x 3 - 1.8
= 9 - 1.8
= 7.2 m

Average height of the chikoo tree and the durian tree
= 7.2 ÷ 2
= 3.6 m

Answer(s): 3.6 m