PSLE There was a total of 24136 cm
3 of water in rectangular tanks P and Q at first. The height of the water level in tank Q was 7 cm above that of tank P.
- Find the height of the water level in tank P.
- Sarah poured 6528 cm3 of water out of tank Q. Tank Q was then half filled with water. What was the height of tank Q?
(a)
Volume of water in Tank Q with a height of 7 cm
= 34 x 24 x 7
= 5712 cm
3 Volume of water in both tanks excluding the water that is 7 cm above that of Tank P
= 24136 - 5712
= 18424 cm
3 Base area of Tank P
= 25 x 20
= 500 cm
2 Base area of Tank Q
= 34 x 24
= 816 cm
2 Combined base areas of both tanks
= 500 + 816
= 1316 cm
2 Height of water in Tank P
= 18424 ÷ 1316
= 14 cm
(b)
Decrease in the height of Tank Q after some water was poured out
= 6528 ÷ 816
= 8 cm
Original height of water before some was poured out
= 14 + 7
= 21 cm
Height of water after some was poured out
= 21 - 8
= 13 cm
Height of Tank P
= 2 x 13
= 26 cm
Answer(s): (a) 14 cm; (b) 26 cm