average of 5 numbers is 12 . if one number is excluded the average becomes 10 . the excluded number is Pick.
A) 35  B) 20  C) 40  D) 30  E) 67

Rationale: explanation : number is ( 5 * 12 ) - ( 4 * 10 ) = 60 - 40 = 20 answer : option b
Answer: B