Correct Answer - Option 4 : 6
Calculation
According to question
⇒ A + (B + C)/2 = 5
⇒ 2A + B + C = 10 ------(i)
⇒ B + (A + C)/2 = 7
⇒ 2B + A + C = 14 ------(ii)
⇒ Adding both equation we get
⇒ 3(A + B )+ 2C = 24 ------(iii)
⇒ Subtract equation (ii) from equation (i), we get
⇒ B - A = 4 ------(iv)
⇒ From option 2 it is not possible that A + B = 4, So option 2 is wrong
⇒ From equation third value of C should be multiple of 3
⇒ Let C = 3 put it in equation (iii)
⇒ 3(A + B) + 6 = 24
⇒ A + B = 18/3
∴ The sum of A and B is 6