PSLE There was a total of 26202 cm
3 of water in rectangular tanks R and S at first. The height of the water level in tank S was 3 cm above that of tank R.
- Find the height of the water level in tank R.
- Elyse poured 5510 cm3 of water out of tank S. Tank S was then half filled with water. What was the height of tank S?
(a)
Volume of water in Tank S with a height of 3 cm
= 38 x 29 x 3
= 3306 cm
3 Volume of water in both tanks excluding the water that is 3 cm above that of Tank R
= 26202 - 3306
= 22896 cm
3 Base area of Tank R
= 31 x 26
= 806 cm
2 Base area of Tank S
= 38 x 29
= 1102 cm
2 Combined base areas of both tanks
= 806 + 1102
= 1908 cm
2 Height of water in Tank R
= 22896 ÷ 1908
= 12 cm
(b)
Decrease in the height of Tank S after some water was poured out
= 5510 ÷ 1102
= 5 cm
Original height of water before some was poured out
= 12 + 3
= 15 cm
Height of water after some was poured out
= 15 - 5
= 10 cm
Height of Tank R
= 2 x 10
= 20 cm
Answer(s): (a) 12 cm; (b) 20 cm