PSLE There was a total of 47604 cm
3 of water in rectangular tanks P and Q at first. The height of the water level in tank Q was 6 cm above that of tank P.
- Find the height of the water level in tank P.
- Marion poured 9282 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 6 cm
= 39 x 34 x 6
= 7956 cm
3 Volume of water in both tanks excluding the water that is 6 cm above that of Tank P
= 47604 - 7956
= 39648 cm
3 Base area of Tank P
= 36 x 32
= 1152 cm
2 Base area of Tank Q
= 39 x 34
= 1326 cm
2 Combined base areas of both tanks
= 1152 + 1326
= 2478 cm
2 Height of water in Tank P
= 39648 ÷ 2478
= 16 cm
(b)
Decrease in the height of Tank Q after some water was poured out
= 9282 ÷ 1326
= 7 cm
Original height of water before some was poured out
= 16 + 6
= 22 cm
Height of water after some was poured out
= 22 - 7
= 15 cm
Height of Tank P
= 2 x 15
= 30 cm
Answer(s): (a) 16 cm; (b) 30 cm