Suppose the can initially contains 7
x and 5
x of mixtures A and B respectively.
Quantity of A in mixture left = |
❨ |
7x - |
7 |
x 9 |
❩ |
litres = |
❨ |
7x - |
21 |
❩ litres. |
12 |
4 |
Quantity of B in mixture left = |
❨ |
5x - |
5 |
x 9 |
❩ |
litres = |
❨ |
5x - |
15 |
❩ litres. |
12 |
4 |
⟹ |
28x - 21 |
= |
7 |
20x + 21 |
9 |
⟹ 252x - 189 = 140x + 147
⟹ 112x = 336
⟹ x = 3.
So, the can contained 21 litres of A.