PSLE There was a total of 27121 cm
3 of water in rectangular tanks Y and Z at first. The height of the water level in tank Z was 3 cm above that of tank Y.
- Find the height of the water level in tank Y.
- Linda poured 5075 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 3 cm
= 35 x 29 x 3
= 3045 cm
3 Volume of water in both tanks excluding the water that is 3 cm above that of Tank Y
= 27121 - 3045
= 24076 cm
3 Base area of Tank Y
= 31 x 27
= 837 cm
2 Base area of Tank Z
= 35 x 29
= 1015 cm
2 Combined base areas of both tanks
= 837 + 1015
= 1852 cm
2 Height of water in Tank Y
= 24076 ÷ 1852
= 13 cm
(b)
Decrease in the height of Tank Z after some water was poured out
= 5075 ÷ 1015
= 5 cm
Original height of water before some was poured out
= 13 + 3
= 16 cm
Height of water after some was poured out
= 16 - 5
= 11 cm
Height of Tank Y
= 2 x 11
= 22 cm
Answer(s): (a) 13 cm; (b) 22 cm