If a : b = 3 : 4 and b : c = 4 : 7, then $$\frac{a + b + c}{c}$$ is equal to:​

Correct option is D

Given:

a : b = 3 : 4

b : c = 4 : 7 

Solution:  ​

a : b = 3 : 4  ......(1)

b : c = 4 : 7 ........(2) 

From both equation

a : b : c = 3 : 4 : 7 

Now,  

​$$\frac{a +b+c}{c} = \frac{3+4+7}{7} = \frac{14}{7} = 2$$​​