351. The average of 13 numbers is 60. Average of the first 7 of them is 57 and that of the last 7 is 61. Find the 8th number?
A. 46
B. 32
C. 68
D. 51

352. Find the average of the first 20 natural numbers?
A. 10
B. 11.5
C. 12
D. 10.5

353. The average of 11 results is 50, if the average of first six results is 49 and that of the last six is 52. Find the sixth result?
A. 46
B. 56
C. 34
D. 57

354. The average of five results is 46 and that of the first four is 45. The fifth result is__________?
A. 1
B. 10
C. 12.5
D. 50

355. Three years ago the average age of a family of six members was 19 years. A boy have been born, the average age of the family is the same today. What is the age of the boy?
A. 1 year
B. 1.5 years
C. 2 years
D. 2.5 years

356. The average salary per head of the entire staff of an office including the officers and clerks is Rs.90. The average salary of officers is Rs.600 and that of the clerks is Rs.84. If the number of officers is 2, find the number of officers in the office?
A. 1540
B. 960
C. 840
D. 1020

357. The average weight of 25 persons sitting in a boat had some value. A new person added to them whose weight was 46 kg only. Due to his arrival, the average weight of all the persons decreased by 5 kg. Find the average weight of first 25 persons?
A. 55 kg
B. 62 kg
C. 56 kg
D. None

358. The average marks in mathematics scored by the students of a school at the public examination were 39. If four of these students who actually scored 5, 12, 15 and 19 marks at the examination had not been sent up, the average marks for the school would have been 44. Find the number of students sent up for examination from the school?
A. 20
B. 25
C. 30
D. 32

359. Nine men went to a hotel. Eight of them spent Rs.3 each over their meals and the ninth spent Rs.2 more than the average expenditure of all the nine. Determine the total money spent by them?
A. Rs.29.25
B. Rs.30.25
C. Rs.32
D. Rs.35

360. A batsman makes a score of 64 runs in the 16th innings and thus increased his average by 3. Find his average after the 16th inning?
A. 17
B. 29
C. 18
D. 19