331. The average of first five prime numbers greater than 20 is____________?
A. 31.00
B. 31.01
C. 32.00
D. 32.2

332. The average of 9 observations was 9, that of the 1st of 5 being 10 and that of the last 5 being 8. What was the 5th observation?
A. 9
B. 8
C. 7
D. 6

333. The average of 1st 3 of 4 numbers is 16 and of the last 3 are 15. If the sum of the first and the last number is 13. What is the last numbers?
A. 8
B. 6
C. 5
D. 2

334. The average age of three boys is 15 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy?
A. 15
B. 9
C. 18
D. 21

335. The average of first 10 odd numbers is_____________?
A. 11
B. 10
C. 12
D. 17

336. The average of first 10 natural numbers is____________?
A. 5
B. 5.5
C. 6.5
D. 6

337.  The average of first ten prime numbers which are odd is____________?
A. 12.9
B. 13.8
C. 15.8
D. 17

338. The average of 11 numbers is 10.9. If the average of first six is 10.5 and that of the last six is 11.4 the sixth number is_____________?
A. 11.0
B. 11.3
C. 11.4
D. 11.5

339. The average of first 10 even numbers is___________?
A. 18
B. 22
C. 9
D. 11

340. The average salary of workers in an industry is Rs.200 the average salary of technicians being Rs.400 and that of non-technicians being Rs.125. What is the total number of workers?
A. 250
B. 275
C. 550
D. 400

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