Quantitative Aptitude Ques 935
Question: A can contains a mixture of two liquids A and B in the ratio of 7: 5. When 9 L of mixture is drained 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 in the can initially?
Options:
A) 10
B) 20
C) 21
D) 25
Show Answer
Answer:
Correct Answer: C
Solution:
- Let the original quantity be $ 12xL. $ In 9 L of the mixture, Liquid A $ =\frac{7}{12}\times 9=\frac{21}{4}L $ Liquid B $ =\frac{5}{12}\times 9=\frac{15}{4}L $ According to the question, $ \frac{7x-\frac{21}{4}}{5x-\frac{15}{4}+9}=\frac{7}{9} $
$ \Rightarrow $ $ \frac{28x-21}{20x-15+36}=\frac{7}{9} $
$ \Rightarrow $ $ \frac{4x-3}{20x+21}=\frac{1}{9} $
$ \Rightarrow $ $ x=3 $
$ \therefore $ Original quantity of liquid $ A=7x=21L $
BETA
