PSLE There was a total of 18208 cm
3 of water in rectangular tanks L and M at first. The height of the water level in tank M was 3 cm above that of tank L.
- Find the height of the water level in tank L.
- Nora poured 4800 cm3 of water out of tank M. Tank M was then half filled with water. What was the height of tank M?
(a)
Volume of water in Tank M with a height of 3 cm
= 30 x 20 x 3
= 1800 cm
3 Volume of water in both tanks excluding the water that is 3 cm above that of Tank L
= 18208 - 1800
= 16408 cm
3 Base area of Tank L
= 26 x 22
= 572 cm
2 Base area of Tank M
= 30 x 20
= 600 cm
2 Combined base areas of both tanks
= 572 + 600
= 1172 cm
2 Height of water in Tank L
= 16408 ÷ 1172
= 14 cm
(b)
Decrease in the height of Tank M after some water was poured out
= 4800 ÷ 600
= 8 cm
Original height of water before some was poured out
= 14 + 3
= 17 cm
Height of water after some was poured out
= 17 - 8
= 9 cm
Height of Tank L
= 2 x 9
= 18 cm
Answer(s): (a) 14 cm; (b) 18 cm