The average of 6 observations is 12. A new seventh observation is included and the new average is decreased by 1. The seventh observation is : Options
A) 1	B) 3	C) 5	D) 6	E) 8

Rationale: "explanation : seventh observation = ( 7 × × 11 - 6 × × 12 ) = 5 correct option : c"
Answer: C