The average of 25 results is 20. The average of first 12 of those is 14 and the average of last 12 is 17. What is the 13th result?
Choices: A) 128 B) 75 C) 69 D) 78 E) 45

Rationale: "solution : sum of 1 st 12 results = 12 * 14 sum of last 12 results = 12 * 17 13 th result = x ( let ) now , 12 * 14 + 12 * 17 + x = 25 * 20 or , x = 128 . answer : option a"
Answer: A