Anna has 2 tanks. Tank V and Tank W are of different capacities. If Tank V is filled by a tap at a rate of 3 litres per minute and Tank W is filled by a tap at a rate of 7 litres per minute, when Tank V is completely filled, 7 litres of water flowed out from Tank W. If Tank V is filled by a tap at a rate of 4 litres per minute and Tank W is filled by a tap at a rate of 2 litres per minute, when Tank V is completely filled, Tank W is only one-quarter-filled. What is the capacity of Tank W? Express your answer in litres.
|
Scenario 1 |
Scenario 2 |
Tank type |
Tank V |
Tank W |
Tank V |
Tank W |
Volume of the tank |
3 u |
7 u - 7 |
4 p |
2 p x 4 = 8 p |
Let 1 u be the time taken for Scenario 1.
Let 1 p be the time taken for Scenario 2.
3 u = 4 p --- (1)
7 u - 7 = 8 p
7 u = 8 p + 7 --- (2)
Make u the same.
(1) x 7
21 u = 28 p --- (3)
(2) x 3
21 u = 24 p + 21 --- (4)
(3) = (4)
28 p = 24 p + 21
28 p - 24 p = 21
4 p = 21
1 p = 21 ÷ 4 = 5.25
Volume of Tank W
= 8 p
= 8 x 5.25
= 42 ℓ
Answer(s): 42 ℓ