PSLE There was a total of 25088 cm
3 of water in rectangular tanks J and K at first. The height of the water level in tank K was 2 cm above that of tank J.
- Find the height of the water level in tank J.
- Kathy poured 6080 cm3 of water out of tank K. Tank K was then half filled with water. What was the height of tank K?
(a)
Volume of water in Tank K with a height of 2 cm
= 38 x 32 x 2
= 2432 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank J
= 25088 - 2432
= 22656 cm
3 Base area of Tank J
= 28 x 24
= 672 cm
2 Base area of Tank K
= 38 x 32
= 1216 cm
2 Combined base areas of both tanks
= 672 + 1216
= 1888 cm
2 Height of water in Tank J
= 22656 ÷ 1888
= 12 cm
(b)
Decrease in the height of Tank K after some water was poured out
= 6080 ÷ 1216
= 5 cm
Original height of water before some was poured out
= 12 + 2
= 14 cm
Height of water after some was poured out
= 14 - 5
= 9 cm
Height of Tank J
= 2 x 9
= 18 cm
Answer(s): (a) 12 cm; (b) 18 cm