PSLE There was a total of 17681 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.
- Kathy poured 3200 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
= 32 x 25 x 2
= 1600 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank X
= 17681 - 1600
= 16081 cm
3 Base area of Tank X
= 23 x 19
= 437 cm
2 Base area of Tank Y
= 32 x 25
= 800 cm
2 Combined base areas of both tanks
= 437 + 800
= 1237 cm
2 Height of water in Tank X
= 16081 ÷ 1237
= 13 cm
(b)
Decrease in the height of Tank Y after some water was poured out
= 3200 ÷ 800
= 4 cm
Original height of water before some was poured out
= 13 + 2
= 15 cm
Height of water after some was poured out
= 15 - 4
= 11 cm
Height of Tank X
= 2 x 11
= 22 cm
Answer(s): (a) 13 cm; (b) 22 cm