PSLE There was a total of 17148 cm
3 of water in rectangular tanks C and D at first. The height of the water level in tank D was 4 cm above that of tank C.
- Find the height of the water level in tank C.
- Shannon poured 2340 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 4 cm
= 26 x 18 x 4
= 1872 cm
3 Volume of water in both tanks excluding the water that is 4 cm above that of Tank C
= 17148 - 1872
= 15276 cm
3 Base area of Tank C
= 21 x 16
= 336 cm
2 Base area of Tank D
= 26 x 18
= 468 cm
2 Combined base areas of both tanks
= 336 + 468
= 804 cm
2 Height of water in Tank C
= 15276 ÷ 804
= 19 cm
(b)
Decrease in the height of Tank D after some water was poured out
= 2340 ÷ 468
= 5 cm
Original height of water before some was poured out
= 19 + 4
= 23 cm
Height of water after some was poured out
= 23 - 5
= 18 cm
Height of Tank C
= 2 x 18
= 36 cm
Answer(s): (a) 19 cm; (b) 36 cm