Riordan has 2 tanks. Tank M and Tank N are of different capacities. If Tank M is filled by a tap at a rate of 4 litres per minute and Tank N is filled by a tap at a rate of 7 litres per minute, when Tank M is completely filled, 8 litres of water flowed out from Tank N. If Tank M is filled by a tap at a rate of 4 litres per minute and Tank N is filled by a tap at a rate of 2 litres per minute, when Tank M is completely filled, Tank N is only one-third-filled. What is the capacity of Tank N? Express your answer in litres.
|
Scenario 1 |
Scenario 2 |
Tank type |
Tank M |
Tank N |
Tank M |
Tank N |
Volume of the tank |
4 u |
7 u - 8 |
4 p |
2 p x 3 = 6 p |
Let 1 u be the time taken for Scenario 1.
Let 1 p be the time taken for Scenario 2.
4 u = 4 p --- (1)
7 u - 8 = 6 p
7 u = 6 p + 8 --- (2)
Make u the same.
(1) x 7
28 u = 28 p --- (3)
(2) x 4
28 u = 24 p + 32 --- (4)
(3) = (4)
28 p = 24 p + 32
28 p - 24 p = 32
4 p = 32
1 p = 32 ÷ 4 = 8
Volume of Tank N
= 6 p
= 6 x 8
= 48 ℓ
Answer(s): 48 ℓ