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

Height of the coconut tree = 1 u
Height of the durian tree = 4 u
Height of the jackfruit tree = 4 u - 1.2

Total height of the jackfruit tree, the coconut tree and the durian 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 jackfruit tree and the coconut 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 jackfruit tree and the coconut tree
= 18.8 ÷ 2
= 9.4 m

Answer(s): 9.4 m