PSLE There was a total of 49160 cm
3 of water in rectangular tanks E and F at first. The height of the water level in tank F was 3 cm above that of tank E.
- Find the height of the water level in tank E.
- Winnie poured 8960 cm3 of water out of tank F. Tank F was then half filled with water. What was the height of tank F?
(a)
Volume of water in Tank F with a height of 3 cm
= 40 x 32 x 3
= 3840 cm
3 Volume of water in both tanks excluding the water that is 3 cm above that of Tank E
= 49160 - 3840
= 45320 cm
3 Base area of Tank E
= 34 x 29
= 986 cm
2 Base area of Tank F
= 40 x 32
= 1280 cm
2 Combined base areas of both tanks
= 986 + 1280
= 2266 cm
2 Height of water in Tank E
= 45320 ÷ 2266
= 20 cm
(b)
Decrease in the height of Tank F after some water was poured out
= 8960 ÷ 1280
= 7 cm
Original height of water before some was poured out
= 20 + 3
= 23 cm
Height of water after some was poured out
= 23 - 7
= 16 cm
Height of Tank E
= 2 x 16
= 32 cm
Answer(s): (a) 20 cm; (b) 32 cm