PSLE There was a total of 14016 cm
3 of water in rectangular tanks M and N at first. The height of the water level in tank N was 4 cm above that of tank M.
- Find the height of the water level in tank M.
- Kimberly poured 4508 cm3 of water out of tank N. Tank N was then half filled with water. What was the height of tank N?
(a)
Volume of water in Tank N with a height of 4 cm
= 28 x 23 x 4
= 2576 cm
3 Volume of water in both tanks excluding the water that is 4 cm above that of Tank M
= 14016 - 2576
= 11440 cm
3 Base area of Tank M
= 22 x 18
= 396 cm
2 Base area of Tank N
= 28 x 23
= 644 cm
2 Combined base areas of both tanks
= 396 + 644
= 1040 cm
2 Height of water in Tank M
= 11440 ÷ 1040
= 11 cm
(b)
Decrease in the height of Tank N after some water was poured out
= 4508 ÷ 644
= 7 cm
Original height of water before some was poured out
= 11 + 4
= 15 cm
Height of water after some was poured out
= 15 - 7
= 8 cm
Height of Tank M
= 2 x 8
= 16 cm
Answer(s): (a) 11 cm; (b) 16 cm