PSLE
There was a total of 16173 cm³ of water in rectangular tanks V and W at first. The height of the water level in tank W was 3 cm above that of tank V.

1. Find the height of the water level in tank V.
2. Rachel poured 3591 cm³ of water out of tank W. Tank W was then half filled with water. What was the height of tank W?

(a)
Volume of water in Tank W with a height of 3 cm
= 27 x 19 x 3
= 1539 cm³

Volume of water in both tanks excluding the water that is 3 cm above that of Tank V
= 16173 - 1539
= 14634 cm³

Base area of Tank V
= 20 x 15
= 300 cm²

Base area of Tank W
= 27 x 19
= 513 cm²

Combined base areas of both tanks
= 300 + 513
= 813 cm²

Height of water in Tank V 
= 14634 ÷ 813
= 18 cm

(b)
Decrease in the height of Tank W after some water was poured out 
= 3591 ÷ 513
= 7 cm

Original height of water before some was poured out
= 18 + 3
= 21 cm

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

Height of Tank V
= 2 x 14
= 28 cm

Answer(s): (a) 18 cm; (b) 28 cm