PSLE There was a total of 14007 cm
3 of water in rectangular tanks Y and Z at first. The height of the water level in tank Z was 7 cm above that of tank Y.
- Find the height of the water level in tank Y.
- Barbara poured 3888 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 7 cm
= 27 x 18 x 7
= 3402 cm
3 Volume of water in both tanks excluding the water that is 7 cm above that of Tank Y
= 14007 - 3402
= 10605 cm
3 Base area of Tank Y
= 17 x 13
= 221 cm
2 Base area of Tank Z
= 27 x 18
= 486 cm
2 Combined base areas of both tanks
= 221 + 486
= 707 cm
2 Height of water in Tank Y
= 10605 ÷ 707
= 15 cm
(b)
Decrease in the height of Tank Z after some water was poured out
= 3888 ÷ 486
= 8 cm
Original height of water before some was poured out
= 15 + 7
= 22 cm
Height of water after some was poured out
= 22 - 8
= 14 cm
Height of Tank Y
= 2 x 14
= 28 cm
Answer(s): (a) 15 cm; (b) 28 cm