PSLE
There was a total of 33344 cm³ of water in rectangular tanks W and X at first. The height of the water level in tank X was 4 cm above that of tank W.

1. Find the height of the water level in tank W.
2. Kylie poured 6384 cm³ of water out of tank X. Tank X was then half filled with water. What was the height of tank X?

(a)
Volume of water in Tank X with a height of 4 cm
= 38 x 28 x 4
= 4256 cm³

Volume of water in both tanks excluding the water that is 4 cm above that of Tank W
= 33344 - 4256
= 29088 cm³

Base area of Tank W
= 29 x 26
= 754 cm²

Base area of Tank X
= 38 x 28
= 1064 cm²

Combined base areas of both tanks
= 754 + 1064
= 1818 cm²

Height of water in Tank W 
= 29088 ÷ 1818
= 16 cm

(b)
Decrease in the height of Tank X after some water was poured out 
= 6384 ÷ 1064
= 6 cm

Original height of water before some was poured out
= 16 + 4
= 20 cm

Height of water after some was poured out
= 20 - 6
= 14 cm

Height of Tank W
= 2 x 14
= 28 cm

Answer(s): (a) 16 cm; (b) 28 cm