What number has to be added to the terms of 3 : 5 to make the ratio 5 : 6? (R.R.B., 2006) · ABC26GN3126

Subject: General Aptitude · Chapter: Ratio and Proportion

What number has to be added to the terms of 3 : 5 to make the ratio 5 : 6? (R.R.B., 2006)

(a)6

(b)7

(c)12

(d)13

Answer

Answer (as printed): B

Explanation

Let the number to be added be $x$. Then, $\frac{3+x}{5+x}=\frac{5}{6} \Rightarrow 6(3+x)=5(5+x)$ $$\Rightarrow 18+6 x=25+5 x \Rightarrow x=7 .$$

Explanation as extracted from the printed page; notation may be imperfect.

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