PSLE There was a total of 22736 cm
3 of water in rectangular tanks B and C at first. The height of the water level in tank C was 6 cm above that of tank B.
- Find the height of the water level in tank B.
- Anna poured 4312 cm3 of water out of tank C. Tank C was then half filled with water. What was the height of tank C?
(a)
Volume of water in Tank C with a height of 6 cm
= 28 x 22 x 6
= 3696 cm
3 Volume of water in both tanks excluding the water that is 6 cm above that of Tank B
= 22736 - 3696
= 19040 cm
3 Base area of Tank B
= 21 x 16
= 336 cm
2 Base area of Tank C
= 28 x 22
= 616 cm
2 Combined base areas of both tanks
= 336 + 616
= 952 cm
2 Height of water in Tank B
= 19040 ÷ 952
= 20 cm
(b)
Decrease in the height of Tank C after some water was poured out
= 4312 ÷ 616
= 7 cm
Original height of water before some was poured out
= 20 + 6
= 26 cm
Height of water after some was poured out
= 26 - 7
= 19 cm
Height of Tank B
= 2 x 19
= 38 cm
Answer(s): (a) 20 cm; (b) 38 cm