PSLE There was a total of 10550 cm
3 of water in rectangular tanks Y and Z at first. The height of the water level in tank Z was 2 cm above that of tank Y.
- Find the height of the water level in tank Y.
- Raeann poured 1900 cm3 of water out of tank Z. Tank Z was then half filled with water. What was the height of tank Z?
(a)
Volume of water in Tank Z with a height of 2 cm
= 25 x 19 x 2
= 950 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank Y
= 10550 - 950
= 9600 cm
3 Base area of Tank Y
= 15 x 11
= 165 cm
2 Base area of Tank Z
= 25 x 19
= 475 cm
2 Combined base areas of both tanks
= 165 + 475
= 640 cm
2 Height of water in Tank Y
= 9600 ÷ 640
= 15 cm
(b)
Decrease in the height of Tank Z after some water was poured out
= 1900 ÷ 475
= 4 cm
Original height of water before some was poured out
= 15 + 2
= 17 cm
Height of water after some was poured out
= 17 - 4
= 13 cm
Height of Tank Y
= 2 x 13
= 26 cm
Answer(s): (a) 15 cm; (b) 26 cm