PSLE There was a total of 25056 cm
3 of water in rectangular tanks H and J at first. The height of the water level in tank J was 6 cm above that of tank H.
- Find the height of the water level in tank H.
- Mary poured 7917 cm3 of water out of tank J. Tank J was then half filled with water. What was the height of tank J?
(a)
Volume of water in Tank J with a height of 6 cm
= 39 x 29 x 6
= 6786 cm
3 Volume of water in both tanks excluding the water that is 6 cm above that of Tank H
= 25056 - 6786
= 18270 cm
3 Base area of Tank H
= 29 x 24
= 696 cm
2 Base area of Tank J
= 39 x 29
= 1131 cm
2 Combined base areas of both tanks
= 696 + 1131
= 1827 cm
2 Height of water in Tank H
= 18270 ÷ 1827
= 10 cm
(b)
Decrease in the height of Tank J after some water was poured out
= 7917 ÷ 1131
= 7 cm
Original height of water before some was poured out
= 10 + 6
= 16 cm
Height of water after some was poured out
= 16 - 7
= 9 cm
Height of Tank H
= 2 x 9
= 18 cm
Answer(s): (a) 10 cm; (b) 18 cm