PSLE There was a total of 12198 cm
3 of water in rectangular tanks D and E at first. The height of the water level in tank E was 3 cm above that of tank D.
- Find the height of the water level in tank D.
- Emily poured 2730 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 3 cm
= 26 x 21 x 3
= 1638 cm
3 Volume of water in both tanks excluding the water that is 3 cm above that of Tank D
= 12198 - 1638
= 10560 cm
3 Base area of Tank D
= 23 x 18
= 414 cm
2 Base area of Tank E
= 26 x 21
= 546 cm
2 Combined base areas of both tanks
= 414 + 546
= 960 cm
2 Height of water in Tank D
= 10560 ÷ 960
= 11 cm
(b)
Decrease in the height of Tank E after some water was poured out
= 2730 ÷ 546
= 5 cm
Original height of water before some was poured out
= 11 + 3
= 14 cm
Height of water after some was poured out
= 14 - 5
= 9 cm
Height of Tank D
= 2 x 9
= 18 cm
Answer(s): (a) 11 cm; (b) 18 cm