Question

m : 3 and 6 : 18 are equivalent ratios. Also, 4 : n and 20 : 25 are equivalent ratios. What is the value of m + n?

• A. 3
• B. 4
• C. 5
• D. 6

Answer 1

The correct option is D 6

$\because$ m : 3 and 6 : 18 are equivalent ratios, their simplest forms are equal.

$\begin{array}{cc}\frac{m}{3}& =\frac{6}{18}\\ \frac{m}{3}& =\frac{1}{3}\end{array}$

Multiplying both sides with 3, we get,

$\Rightarrow$ m = 1

Also,
20:25 $\Rightarrow$ (4 $\times$ 5):(5 $\times$ 5) = 4:5

$\because$ 4 : n and 20 : 25 are equivalent ratios, their simplest forms are equal.

$\begin{array}{cc}\frac{4}{n}& =\frac{20}{25}\\ \frac{4}{n}& =\frac{4}{5}\end{array}$

On solving

n = 5

$\therefore$ m + n = 1 + 5 = 6