3 friends A, B, C went for week end party to McDonald’s restaurant and there they measure there weights in some order In 7 rounds. A, B, C, AB, BC, AC, ABC. Final round measure is 160kg then find the average weight of all the 7 rounds?
Choose the correct choice from the following options
A) 91.4 kgs  B) 88.5 kgs  C) 86.5 kgs  D) 67.5 kgs  E) 88.2 kgs

Rationale: average weight = [ ( a + b + c + ( a + b ) + ( b + c ) + ( c + a ) + ( a + b + c ) ] / 7 = 4 ( a + b + c ) / 7 = 4 x 160 / 7 = 91.4 kgs answer : a
Answer: A