PSLE
There was a total of 26531 cm³ of water in rectangular tanks G and H at first. The height of the water level in tank H was 4 cm above that of tank G.

1. Find the height of the water level in tank G.
2. Winnie poured 6237 cm³ of water out of tank H. Tank H was then half filled with water. What was the height of tank H?

(a)
Volume of water in Tank H with a height of 4 cm
= 33 x 27 x 4
= 3564 cm³

Volume of water in both tanks excluding the water that is 4 cm above that of Tank G
= 26531 - 3564
= 22967 cm³

Base area of Tank G
= 23 x 20
= 460 cm²

Base area of Tank H
= 33 x 27
= 891 cm²

Combined base areas of both tanks
= 460 + 891
= 1351 cm²

Height of water in Tank G 
= 22967 ÷ 1351
= 17 cm

(b)
Decrease in the height of Tank H after some water was poured out 
= 6237 ÷ 891
= 7 cm

Original height of water before some was poured out
= 17 + 4
= 21 cm

Height of water after some was poured out
= 21 - 7
= 14 cm

Height of Tank G
= 2 x 14
= 28 cm

Answer(s): (a) 17 cm; (b) 28 cm