PSLE There was a total of 18180 cm
3 of water in rectangular tanks K and L at first. The height of the water level in tank L was 4 cm above that of tank K.
- Find the height of the water level in tank K.
- Shiyun poured 3120 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 4 cm
= 26 x 20 x 4
= 2080 cm
3 Volume of water in both tanks excluding the water that is 4 cm above that of Tank K
= 18180 - 2080
= 16100 cm
3 Base area of Tank K
= 19 x 15
= 285 cm
2 Base area of Tank L
= 26 x 20
= 520 cm
2 Combined base areas of both tanks
= 285 + 520
= 805 cm
2 Height of water in Tank K
= 16100 ÷ 805
= 20 cm
(b)
Decrease in the height of Tank L after some water was poured out
= 3120 ÷ 520
= 6 cm
Original height of water before some was poured out
= 20 + 4
= 24 cm
Height of water after some was poured out
= 24 - 6
= 18 cm
Height of Tank K
= 2 x 18
= 36 cm
Answer(s): (a) 20 cm; (b) 36 cm