1 . 8 years ago, the ratio of A's age to B's age was 4 :5 At present the ratio of B's age and C's age is 4 : 5 At present , the difference between A's age and C's age is 20 years, then what is the sum of the ages of A, B and C?

• A. 138 years
• B. 164 years
• C. 148 years
• D. 152 years

Answer: Option C

Explanation:

A:B  = 4 :5 [8 years ago] 
 = 32:40 [multiplying by 12]
 = 32   +  8:40   +  8 [present]
 = 40 :48
B:C  = 4 : 5
 = 48 : 60 [multiplying by 12]
∴ A :B :C  = 40 : 48 : 60 
The sum of the ages of 
A,B and C 
 = 40   +  48   +  60 
 = 148 years