PSLE There was a total of 16732 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.
- Penelope poured 2000 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
= 25 x 20 x 2
= 1000 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank X
= 16732 - 1000
= 15732 cm
3 Base area of Tank X
= 22 x 17
= 374 cm
2 Base area of Tank Y
= 25 x 20
= 500 cm
2 Combined base areas of both tanks
= 374 + 500
= 874 cm
2 Height of water in Tank X
= 15732 ÷ 874
= 18 cm
(b)
Decrease in the height of Tank Y after some water was poured out
= 2000 ÷ 500
= 4 cm
Original height of water before some was poured out
= 18 + 2
= 20 cm
Height of water after some was poured out
= 20 - 4
= 16 cm
Height of Tank X
= 2 x 16
= 32 cm
Answer(s): (a) 18 cm; (b) 32 cm