CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average of 10 numbers is 45. If each number is increased by 5, what is the new average?
A. 45
B. 49
C. 50
D. 55
Correct Answer: C
Adding 5 to every observation adds 5 to the average.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
What is the average of the first 20 odd natural numbers?
A. 21
B. 40
C. 19
D. 20
Correct Answer: D
The average of the first n odd numbers is n; for n=20, it is 20.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
What is the average of the first 10 natural numbers?
A. 5
B. 10
C. 6
D. 5.5
Correct Answer: D
Average of 1 to n=(n+1)/2. For n=10, average=5.5.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
Six consecutive even integers have an average of 21. What is the smallest integer?
A. 20
B. 18
C. 16
D. 14
Correct Answer: C
The six integers are 16,18,20,22,24,26, whose average is 21.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
Seven consecutive integers have an average of 31. What is the largest integer?
A. 34
B. 35
C. 31
D. 33
Correct Answer: A
The middle integer is 31. Three greater integers are 32,33,34, so largest=34.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average age of five people is 24. If a 20-year-old leaves, what is the average age of the remaining four?
A. 24
B. 26
C. 25
D. 23
Correct Answer: C
Original total=120. Remaining total=100. Average=100/4=25.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average age of 15 men is 40 and of 10 women is 35. What is the combined average?
A. 38
B. 37
C. 39
D. 36
Correct Answer: A
Combined total=600+350=950; total persons=25; average=38.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average marks of 20 students is 60 and of 30 students is 70. What is the combined average?
A. 68
B. 66
C. 65
D. 64
Correct Answer: B
Combined average=(20×60+30×70)/50=3300/50=66.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average of eight numbers is 25. If 32 is replaced by 40, what is the new average?
A. 25
B. 27
C. 26
D. 28
Correct Answer: C
Total increases by 8. Average increases by 8/8=1, becoming 26.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average of six numbers is 18. If one number is removed, the average of the remaining five is 16. What number was removed?
A. 18
B. 24
C. 28
D. 30
Correct Answer: C
Original total=108; remaining total=80. Removed number=28.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average of 8, 12, x and 20 is 14. Find x.
A. 14
B. 16
C. 20
D. 18
Correct Answer: B
Required total=4×14=56. Known total=40, so x=16.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
Find the average of 2, 4, 6, 8 and 10.
A. 5
B. 7
C. 6
D. 8
Correct Answer: C
Sum=30 and count=5, so average=6.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
What is the average of the first five natural numbers?
A. 5
B. 2.5
C. 3
D. 4
Correct Answer: C
(1+2+3+4+5)/5=15/5=3.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average of five numbers is 12. What is their total?
A. 55
B. 72
C. 50
D. 60
Correct Answer: D
Total=average×number of values=12×5=60.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
Find the arithmetic mean of 10, 20 and 30.
A. 20
B. 15
C. 30
D. 25
Correct Answer: A
Mean=(10+20+30)/3=20.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average of 10, 20 and 30 is:
A. 10
B. 15
C. 20
D. 30
Correct Answer: C
C: Correct because the sum is 60 and 60 divided by 3 is 20. A: Wrong because 10 is only one value, not the average. B: Wrong because 15 is too low. D: Wrong because 30 is the largest value, not the average.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The median of 2, 5 and 8 is:
A. 2
B. 5
C. 7
D. 8
Correct Answer: B
A: Wrong because 2 is the lowest value. B: Correct because 5 is the middle value when the data are ordered. C: Wrong because 7 is not in the given data and is not the median. D: Wrong because 8 is the highest value.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
The average of 4, 8 and 12 is:
A. 6
B. 8
C. 10
D. 12
Correct Answer: B
A: Wrong because the sum 24 divided by 3 is not 6. B: Correct because (4+8+12)/3 = 24/3 = 8. C: Wrong because 10 is higher than the calculated mean. D: Wrong because 12 is only one value, not the average.
CSS - PMS - CCE - PCS - Mathematics
Average / Arithmetic Mean
Average of 10, 20 and 30 = ?
A. 15
B. 20
C. 25
D. 30
Correct Answer: B
Correct Answer: B. 20
Fact Check: (10 + 20 + 30) ÷ 3 = 20.
A. 15 is not correct because it is lower than the correct figure, 20.
B. Correct — 20 is right because (10 + 20 + 30) ÷ 3 = 20.
C. 25 is not correct because it is higher than the correct figure, 20.
D. 30 is not correct because it is higher than the correct figure, 20.