PSLE There was a total of 26640 cm
3 of water in rectangular tanks C and D at first. The height of the water level in tank D was 6 cm above that of tank C.
- Find the height of the water level in tank C.
- Jaslyn poured 6860 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 6 cm
= 35 x 28 x 6
= 5880 cm
3 Volume of water in both tanks excluding the water that is 6 cm above that of Tank C
= 26640 - 5880
= 20760 cm
3 Base area of Tank C
= 30 x 25
= 750 cm
2 Base area of Tank D
= 35 x 28
= 980 cm
2 Combined base areas of both tanks
= 750 + 980
= 1730 cm
2 Height of water in Tank C
= 20760 ÷ 1730
= 12 cm
(b)
Decrease in the height of Tank D after some water was poured out
= 6860 ÷ 980
= 7 cm
Original height of water before some was poured out
= 12 + 6
= 18 cm
Height of water after some was poured out
= 18 - 7
= 11 cm
Height of Tank C
= 2 x 11
= 22 cm
Answer(s): (a) 12 cm; (b) 22 cm