Ratio And Proportion Ques 31
Question-
The respective ratio between the present ages of $A$ and $B$ is 9 : 10. 8 years ago the respective ratio of $\frac{1}{7}$ th of A’s age that time and $\frac{1}{4}$ th of B’s age that time was $1: 2$. What will be the respective ratio between A’s age and B’s age 8 years hence?
(1) $17: 18$
(2) $11: 12$
(3) $9: 11$
(4) $12: 13$
(5) $15: 17$
(IBPS RRBs Officer CWE (Prelim Exam) 16.09.2017)
Show Answer
Correct Answer: (2)
Solution: (2)
A’s present age $=9 x$ years
B’s present age $=10 x$ years
According to the question,
$=\frac{\frac{9 x-8}{7}}{\frac{10 x-8}{4}}=\frac{1}{2} $
$ \Rightarrow \frac{9 x-8}{10 x-8}=\frac{1}{2} \times \frac{7}{4}=\frac{7}{8}$
$\Rightarrow \frac{9 x-8}{5 x-4}=\frac{7}{4} $
$\Rightarrow 36 x-32=35 x-28 $
$ \Rightarrow x=32-28=4$
$\therefore$ Required ratio $=\frac{9 x+8}{10 x+8}$ $ =\frac{9 \times 4+8}{10 \times 4+8} $ $=\frac{44}{48}=\frac{11}{12}=11: 12$
BETA
