Let scores of A, B and C are and respectively. According to ques, ⇒ a+b=120 ----(i) b+c=130 -----(ii) c+a=140 -----(iii) Adding above equations, we get : 2(a+b+c)=(120+130+140) ⇒ a+b+c=
390
2
=195 Substituting value from equation (i) in above equation, ⇒ 120+c=195 ⇒ c=195−120=75