PSLE There was a total of 20656 cm
3 of water in rectangular tanks U and V at first. The height of the water level in tank V was 3 cm above that of tank U.
- Find the height of the water level in tank U.
- Zoe poured 6400 cm3 of water out of tank V. Tank V was then half filled with water. What was the height of tank V?
(a)
Volume of water in Tank V with a height of 3 cm
= 32 x 25 x 3
= 2400 cm
3 Volume of water in both tanks excluding the water that is 3 cm above that of Tank U
= 20656 - 2400
= 18256 cm
3 Base area of Tank U
= 24 x 21
= 504 cm
2 Base area of Tank V
= 32 x 25
= 800 cm
2 Combined base areas of both tanks
= 504 + 800
= 1304 cm
2 Height of water in Tank U
= 18256 ÷ 1304
= 14 cm
(b)
Decrease in the height of Tank V after some water was poured out
= 6400 ÷ 800
= 8 cm
Original height of water before some was poured out
= 14 + 3
= 17 cm
Height of water after some was poured out
= 17 - 8
= 9 cm
Height of Tank U
= 2 x 9
= 18 cm
Answer(s): (a) 14 cm; (b) 18 cm