PSLE There was a total of 33680 cm
3 of water in rectangular tanks F and G at first. The height of the water level in tank G was 5 cm above that of tank F.
- Find the height of the water level in tank F.
- Julie poured 7440 cm3 of water out of tank G. Tank G was then half filled with water. What was the height of tank G?
(a)
Volume of water in Tank G with a height of 5 cm
= 40 x 31 x 5
= 6200 cm
3 Volume of water in both tanks excluding the water that is 5 cm above that of Tank F
= 33680 - 6200
= 27480 cm
3 Base area of Tank F
= 35 x 30
= 1050 cm
2 Base area of Tank G
= 40 x 31
= 1240 cm
2 Combined base areas of both tanks
= 1050 + 1240
= 2290 cm
2 Height of water in Tank F
= 27480 ÷ 2290
= 12 cm
(b)
Decrease in the height of Tank G after some water was poured out
= 7440 ÷ 1240
= 6 cm
Original height of water before some was poured out
= 12 + 5
= 17 cm
Height of water after some was poured out
= 17 - 6
= 11 cm
Height of Tank F
= 2 x 11
= 22 cm
Answer(s): (a) 12 cm; (b) 22 cm