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Averages ( 16 to 20 ):
APTITUDE QUESTIONS (AVERAGES):
16. The average age of a group of persons going for movie is 16 years. Twenty new persons with an average age 15 years join the group on the spot due to which their average age becomes 15.5 years. The number of persons initially going for movie is:
A) 15
B) 40
C) 20
D) 30
E) None of these
View Answer
Answer: option (C)
Explanation:
Let the number of persons be x. Then,
16x + 20 * 15 = 15.5(x + 20) => 0.5x = 10 => x = 20
17. The batting average for 40 innings of a cricket player is 50 runs. The player highest score exceeds lowest score by 172 runs. If we exclude these two innings, then the average of the remaining 38 innings is 48 runs. The highest score of the player is:
A) 175 runs
B) 180 runs
C) 172 runs
D) 174 runs
E) None of these
View Answer
Answer: option (D)
Explanation:
Let the highest score be x. Then, lowest score = (x – 172)
Then, (50 * 40) – [x + (x – 172)] = 38 * 48
=>2x = 2000 + 172 – 1824 => 2x = 348
=>x = 174
18. Eight persons went to a hotel for taking their meals. Seven of them spent Rs. 14 each on their meals and the eighth spent Rs. 10 more than the average expenditure of all the nine. What was the total money spent by them?
A) Rs.120
B) Rs.117
C) Rs.125
D) Rs.130
E) None of these
View Answer
Answer: option (A)
Explanation:
Let the average expenditure of all the nine be Rs. x
Then, 14 * 7 + (x + 7) = 8x or 7x = 105 or x = 15
∴ Total money spent = 8x = Rs. (8 * 15) = Rs.120
19. The average of 12 results is 50. If the average of first six results is 60 and that of the last six is 65, find the sixth result.
A) 150
B) 76
C) 86
D) 96
E) None of these
View Answer
Answer: option (A)
Explanation:
Sixth result = (60 * 6 + 65 * 6 – 50 * 12) = 150
20. The average of first five multiples of 3 is:
A) 6
B) 9
C) 3
D) 12
E) None of these
View Answer
Answer: option (B)
Explanation:
Average = 3[ (1+2+3+4+5)/5 ]=45/5=9