The average of 17 numbers is 59. Average of the first 9 of them is 56 and that of the last 9 is 63. Find the 9th number?
Choose the correct option
A) 64 B) 68 C) 65 D) 66 E) 67

Rationale: sum of all the 17 numbers = 17 * 59 = 1,003 sum of the first 9 of them = 9 * 56 = 504 sum of the last 9 of them = 9 * 63 = 567 so , the 8 th number = 504 + 567 - 1,003 = 68 . answer : b
Answer: B