PSLE There was a total of 16518 cm
3 of water in rectangular tanks D and E at first. The height of the water level in tank E was 2 cm above that of tank D.
- Find the height of the water level in tank D.
- Roshel poured 3840 cm3 of water out of tank E. Tank E was then half filled with water. What was the height of tank E?
(a)
Volume of water in Tank E with a height of 2 cm
= 32 x 24 x 2
= 1536 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank D
= 16518 - 1536
= 14982 cm
3 Base area of Tank D
= 27 x 22
= 594 cm
2 Base area of Tank E
= 32 x 24
= 768 cm
2 Combined base areas of both tanks
= 594 + 768
= 1362 cm
2 Height of water in Tank D
= 14982 ÷ 1362
= 11 cm
(b)
Decrease in the height of Tank E after some water was poured out
= 3840 ÷ 768
= 5 cm
Original height of water before some was poured out
= 11 + 2
= 13 cm
Height of water after some was poured out
= 13 - 5
= 8 cm
Height of Tank D
= 2 x 8
= 16 cm
Answer(s): (a) 11 cm; (b) 16 cm