A can contains a mixture of two liquids A and B in the ratio 7 : 5. When 9 litres of mixture are drawn off… · ABC26GN3973
Subject: General Aptitude · Chapter: Alligation or Mixture
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. How many litres of liquid A was contained by the can initially?
(a)10
(b)20
(c)21
(d)25
Answer
Answer: C ✓ checked by 4AB · confidence high
Explanation
Let the can hold T litres. After drawing 9 L, A = 7(T − 9)/12 and B = 5(T − 9)/12 + 9. A : B = 7 : 9 gives 9(T − 9)/12 = 5(T − 9)/12 + 9 ⇒ T − 9 = 27 ⇒ T = 36, so A initially = 7/12 × 36 = 21 L.