PSLE There was a total of 23996 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.
- Erika poured 4712 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
= 38 x 31 x 2
= 2356 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank D
= 23996 - 2356
= 21640 cm
3 Base area of Tank D
= 34 x 29
= 986 cm
2 Base area of Tank E
= 38 x 31
= 1178 cm
2 Combined base areas of both tanks
= 986 + 1178
= 2164 cm
2 Height of water in Tank D
= 21640 ÷ 2164
= 10 cm
(b)
Decrease in the height of Tank E after some water was poured out
= 4712 ÷ 1178
= 4 cm
Original height of water before some was poured out
= 10 + 2
= 12 cm
Height of water after some was poured out
= 12 - 4
= 8 cm
Height of Tank D
= 2 x 8
= 16 cm
Answer(s): (a) 10 cm; (b) 16 cm