Quantitative Aptitude Ques 810

Question: If 30% of $ (B-A) $ is equal to 18% of $ (B+A), $ then the ratio of A : B is equal to

Options:

A) 4 : 1

B) 1 : 4

C) 6 : 4

D) 5 : 9

Show Answer

Answer:

Correct Answer: B

Solution:

  • Given, 30% of $ (B-A)=18%(A+B) $

$ \Rightarrow $ $ (B-A)\times \frac{30}{100}=(A+B)\times \frac{18}{100} $

$ \Rightarrow $ $ \frac{B-A}{B+A}=\frac{18}{30}=\frac{9}{15}=\frac{3}{5} $ By componendo and dividendo If $ \frac{a}{b}=\frac{c}{d}, $ then $ \frac{a+b}{a-b}=\frac{c+d}{c-d} $

$ \Rightarrow $ $ \frac{2B}{-2A}=\frac{3+5}{3-5}=\frac{8}{-2} $

$ \Rightarrow $ $ \frac{B}{A}=\frac{4}{1} $

$ \therefore $ $ \frac{A}{B}=\frac{1}{4} $