PSLE
There was a total of 47906 cm³ of water in rectangular tanks W and X at first. The height of the water level in tank X was 3 cm above that of tank W.

1. Find the height of the water level in tank W.
2. Kylie poured 5304 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 3 cm
= 39 x 34 x 3
= 3978 cm³

Volume of water in both tanks excluding the water that is 3 cm above that of Tank W
= 47906 - 3978
= 43928 cm³

Base area of Tank W
= 34 x 29
= 986 cm²

Base area of Tank X
= 39 x 34
= 1326 cm²

Combined base areas of both tanks
= 986 + 1326
= 2312 cm²

Height of water in Tank W 
= 43928 ÷ 2312
= 19 cm

(b)
Decrease in the height of Tank X after some water was poured out 
= 5304 ÷ 1326
= 4 cm

Original height of water before some was poured out
= 19 + 3
= 22 cm

Height of water after some was poured out
= 22 - 4
= 18 cm

Height of Tank W
= 2 x 18
= 36 cm

Answer(s): (a) 19 cm; (b) 36 cm