PSLE There was a total of 41868 cm
3 of water in rectangular tanks K and L at first. The height of the water level in tank L was 6 cm above that of tank K.
- Find the height of the water level in tank K.
- Olivia poured 7980 cm3 of water out of tank L. Tank L was then half filled with water. What was the height of tank L?
(a)
Volume of water in Tank L with a height of 6 cm
= 38 x 30 x 6
= 6840 cm
3 Volume of water in both tanks excluding the water that is 6 cm above that of Tank K
= 41868 - 6840
= 35028 cm
3 Base area of Tank K
= 31 x 26
= 806 cm
2 Base area of Tank L
= 38 x 30
= 1140 cm
2 Combined base areas of both tanks
= 806 + 1140
= 1946 cm
2 Height of water in Tank K
= 35028 ÷ 1946
= 18 cm
(b)
Decrease in the height of Tank L after some water was poured out
= 7980 ÷ 1140
= 7 cm
Original height of water before some was poured out
= 18 + 6
= 24 cm
Height of water after some was poured out
= 24 - 7
= 17 cm
Height of Tank K
= 2 x 17
= 34 cm
Answer(s): (a) 18 cm; (b) 34 cm