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Averages ( 21 to 25 ):

# APTITUDE QUESTIONS (AVERAGES):

21. The average of five numbers is 29. If we exclude one number, the average becomes 27. The excluded number is:

A) 25

B) 27

C) 30

D) 37

E) None of these

View Answer

Answer: option (D)

Explanation:

Excluded Number = (29 * 5) – (27 * 4) = 145 – 108 = 37

22. The average of six numbers is 4.95. The average of two of them is 4.5, while the average of the other two is 4.85. Find the average of remaining two numbers.

A) 4.5

B) 5.5

C) 4.7

D) 4.8

E) None of these

View Answer

Answer: option (B)

Explanation:

Sum of the remaining two numbers = (4.95 * 6) – [(4.5 * 2) + (4.85 * 2)]
= 29.70 – (9 + 9.7) = 29.70 – 18.7 = 11

∴ Required average = 11/2=5.5

23. A seller has a sale of Rs. 5435, Rs.5927, Rs.5855, Rs.6230 and Rs.7562 for 5 consecutive months. How much sale he must have in the sixth month so that he gets an average sale of Rs.7500?

A) Rs.13991

B) Rs.15991

C) Rs.16001

D) Rs.16991

E) None of these

View Answer

Answer: option (A)

Explanation:

Total sale for 5 months = Rs. (5435 + 5927 + 5855 + 6230 + 7562) = Rs.31009

∴ required sale = Rs. [(7500 * 6) – 31009] = Rs. (45000 – 31009) = Rs.13991

24. The mean of 40 observations was 26. Later it was assume that an observation 38 was wrongly taken as 13. The corrected new mean is:

A) 25.2

B) 26.1

C) 26.6

D) 29.1

E) None of these

View Answer

Answer: option (C)

Explanation:

Correct sum = (26 * 40 + 38 – 13) = 1065

∴ correct mean = 1065/40 = 26.6

25. The average salary of all the laborers in a workshop is Rs. 12000. The average salary of 7 electricians is Rs. 16000 and the average salary of the rest is Rs. 10000. Find the total number of laborers in the workshop.

A) 25

B) 21

C) 24

D) 23

E) None of these

View Answer

Answer: option (B)

Explanation:

Let the total number of laborers be x. Then,

12000x = (16000 * 7) + 10000 (x – 7) => 2000x = 42000 => x = 21