PSLE There was a total of 15530 cm
3 of water in rectangular tanks X and Y at first. The height of the water level in tank Y was 2 cm above that of tank X.
- Find the height of the water level in tank X.
- Shannon poured 3120 cm3 of water out of tank Y. Tank Y was then half filled with water. What was the height of tank Y?
(a)
Volume of water in Tank Y with a height of 2 cm
= 26 x 20 x 2
= 1040 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank X
= 15530 - 1040
= 14490 cm
3 Base area of Tank X
= 19 x 15
= 285 cm
2 Base area of Tank Y
= 26 x 20
= 520 cm
2 Combined base areas of both tanks
= 285 + 520
= 805 cm
2 Height of water in Tank X
= 14490 ÷ 805
= 18 cm
(b)
Decrease in the height of Tank Y after some water was poured out
= 3120 ÷ 520
= 6 cm
Original height of water before some was poured out
= 18 + 2
= 20 cm
Height of water after some was poured out
= 20 - 6
= 14 cm
Height of Tank X
= 2 x 14
= 28 cm
Answer(s): (a) 18 cm; (b) 28 cm