If $$\frac{a}{b} = \frac{7}{9},{\text{ }}\frac{b}{c} = \frac{3}{5}{\text{,}}$$    then the value of a : b : c is?

A. 7 : 9 : 15

B. 7 : 9 : 5

C. 21 : 35 : 45

D. 7 : 3 : 15

Answer: Option A

Solution(By Examveda Team)

$$\eqalign{ & {\text{ }}\frac{a}{b} = \frac{7}{9},{\text{ }}\frac{b}{c} = \frac{3}{5} \cr & \therefore a\,\,\,:\,\,\,b\,\,\,:\,\,\,c \cr & \,\,\,\,\,7\,\,\,:\,\,\,9 \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{3_{ \times 3}}:\,\,\,{5_{ \times 3}} \cr & \overline {{\text{ }}\,\,{\text{ }}7\,\,\,:\,\,\,\,9\,\,:\,\,15{\text{ }}} \cr} $$