### Question

**If a + b = 12 ,**

**b + c = 17 **

**and c + a = 11 what is the value of a + b + c?**

A. 10

B. 12

C. 20

D. 18

#### Answer: C. 20

**Solution:**

a + b = 12 …(A)

b + c = 17 …(B)

c + a = 11 …(C)

Adding (A), (B) and (C) we get,

2(a + b + c) = 40

Dividing both sides by 2 we get,

**a + b + c = 20**