PSLE There was a total of 27423 cm
3 of water in rectangular tanks C and D at first. The height of the water level in tank D was 2 cm above that of tank C.
- Find the height of the water level in tank C.
- Emily poured 3720 cm3 of water out of tank D. Tank D was then half filled with water. What was the height of tank D?
(a)
Volume of water in Tank D with a height of 2 cm
= 31 x 24 x 2
= 1488 cm
3 Volume of water in both tanks excluding the water that is 2 cm above that of Tank C
= 27423 - 1488
= 25935 cm
3 Base area of Tank C
= 27 x 23
= 621 cm
2 Base area of Tank D
= 31 x 24
= 744 cm
2 Combined base areas of both tanks
= 621 + 744
= 1365 cm
2 Height of water in Tank C
= 25935 ÷ 1365
= 19 cm
(b)
Decrease in the height of Tank D after some water was poured out
= 3720 ÷ 744
= 5 cm
Original height of water before some was poured out
= 19 + 2
= 21 cm
Height of water after some was poured out
= 21 - 5
= 16 cm
Height of Tank C
= 2 x 16
= 32 cm
Answer(s): (a) 19 cm; (b) 32 cm