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A can contains a mixture of two liquids A and B in the ratio 7 : 5. When 9 litres of mixture are drawn off and the can is filled with B, the ratio of A and B becomes 7 : 9. Litres of liquid A
contained by the can initially was
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- 10
- 20
- 21
- 25
Correct Option: C
Let A = 7x litre, B = 5x litre
In 9 litres of mixture,
A = | × 9 = | litres | ||
12x | 4 |
B = | × 9 = | litres | ||
12x | 4 |
In new situation,
7x − | = 7/9 | |||
4 | ||||
5x − | + 9 | |||
4 |
⇒ | = | ||
20x − 15 + 36 | 9 |
⇒ 252x – 189 = 140x + 147
⇒ 112x = 336 ⇒ x = 3
∴ Initial quantity of liquid A
= 7x = 7 × 3 = 21 litres