PSLE There was a total of 34332 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.
- Gem poured 5920 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
= 37 x 32 x 3
= 3552 cm
3 Volume of water in both tanks excluding the water that is 3 cm above that of Tank L
= 34332 - 3552
= 30780 cm
3 Base area of Tank L
= 31 x 28
= 868 cm
2 Base area of Tank M
= 37 x 32
= 1184 cm
2 Combined base areas of both tanks
= 868 + 1184
= 2052 cm
2 Height of water in Tank L
= 30780 ÷ 2052
= 15 cm
(b)
Decrease in the height of Tank M after some water was poured out
= 5920 ÷ 1184
= 5 cm
Original height of water before some was poured out
= 15 + 3
= 18 cm
Height of water after some was poured out
= 18 - 5
= 13 cm
Height of Tank L
= 2 x 13
= 26 cm
Answer(s): (a) 15 cm; (b) 26 cm