If A : B = 3 : 5 and B : C = 4 : 7, then the value of A : B : C is:

Correct option is D

Given:

$A:B=3:5$

$B:C=4:7$

Solution:

From $A:B=3:5$, we know that $B=5$.

From $B:C=4:7$, we know that $B=4$.

To make these equal, we multiply the first ratio $A:B=3:5$ by 4, and the second ratio $B:C=4:7$ by 5.

A : B = 3×4 : 5×4 = 12 : 20 

B : C = 4×5 : 7×5 = 20 : 35

Now, we have:

A : B = 12 : 20  and  B : C = 20 : 35

Combined ratio: B=20B = 20 ratio:

A : B : C = 12 : 20 : 35​

Thus, the value of A : B : C = 12 : 20 : 35 .