# Average Questions for SSC/RRB Exams (03 – 04 – 2018)

Average Questions for SSC/RRB Exams (03 – 04 – 2018)
1. The average age of 18 boys and their teacher is 12 years. If the teacher’s age is excluded, the average age reduces by 3. What is the teacher’s age?
a) 41 years
b) 51 years
c) 47 years
d) 66 years
Answer: D)
Explanation: Given, average age of 18 boys and their teacher is 12 years
Average = (sum of ages of boys and teacher)/(number of boys and teacher)
12 = (sum of ages of boys and teachers)/19
Sum of ages of boys and teacher = 12 × 19 = 228 years
When teachers age is excluded then average reduced by 3
New average = 9
Average = (sum of ages)/number
9 = sum/18
sum of ages of boys = 162 years
the age of teacher = (228 - 162) years = 66 years
2. The average score of a cricketer for ten matches is 38.9 runs. Find the average for the last four matches if the average for the first six matches is 42.
a) 33.12
b) 23.65
c) 34.25
d) 30.74
Answer: C)
Explanation: Total score of last 4 matches = (10 × 38.9) – (6 × 42) = 389 – 252 = 137
Average for last four matches = 137/4 = 34.25

3. The average of five consecutive even numbers is 40. What is the value of smallest of these numbers?
a) 35
b) 36
c) 44
d) 48
Answer: B)
Explanation: From the given data,
Let us consider five consecutive even numbers be x, x + 2, x + 4, x + 6, x + 8
(x + x + 2 + x + 4 + x + 6 + x + 8)/5 = 40
5x + 20 = 200
5x = 180
x = 180/5 = 36
Smallest of the numbers is 36
4. The average of 7 numbers is 25. The average of 1st two numbers is 32.5 and average of next three numbers is 12.5. If the 6th number is 10.5 less than the 7th number, then find the last number.
a) 18.5
b) 29
c) 31
d) 41.5
Answer: D)
Explanation: Average of 7 numbers = 25
Therefore, sum of all 7 numbers = 7 × 25 = 175
Now, Average of 1st two numbers = 32.5
Therefore, Sum of 1st two numbers = 2 × 32.5 = 65
And, Average of next 3 numbers = 12.5
Therefore, Sum of next three numbers = 3 × 12.5 = 37.5
Hence, Sum of last two numbers = 175 – (65 + 37.5) = 72.5
Let the two numbers be X and Y.
X + Y = 72.5
And, X + 10.5 = Y
Solving, we get,
X = 31 and Y = 41.5
5. If the sum of a few numbers is 480 and their mean is 32 and if another number 80 is included, the mean would become
a) 35
b) 38
c) 40
d) 45
Answer: A)
Explanation: Mean = sum of observations/Number of observations
Given, sum of a few numbers is 480 and their mean is 32
Total no. of numbers taken = 480/32 = 15
Now, another number 80 is included.
Sum of observations = 480 + 80 = 560
Mean = 560/16 = 35
6. The average of ten numbers is 45. If 5 is added to four numbers, the new average is
a) 50
b) 45.5
c) 47
d) 49.5
Answer: C)
Explanation: Average of 10 numbers = 45
Sum of 10 numbers = 45 × 10 = 450
If 5 is added to four numbers:
Sum of 10 numbers = 450 + 5 × 4 = 470
Average of 10 numbers = 470/10 = 47
New average = 47
7. The average age of a 15-member cricket squad is 19 years, if the coach’s age is included, the average increase to 22 years. What is the coach’s age?
a) 67 years
b) 52 years
c) 37 years
d) 44 years
Answer: A)
Explanation: Given, Average age of 15 members = 19
Sum of ages of 15 members = 15 × 19 = 285
Given, if the coach’s age is also included, we have average as 22 years.
(285 + Age of coach)/16 = 22
285 + Age of coach = 16 × 22 = 352
Age of coach = 352 285 = 67 years

8. A batsman in his 12th innings makes a score of 79 runs and thereby increase his average score by 1. What is his average after the 12th innings?
a) 71
b) 65
c) 67
d) 68
Answer: D)
Explanation: Let average score of first 11 innings be x runs.
Then, total runs made by the batsman in 11 innings = 11x
According to the question, after 12th inning, average score = x + 1
Therefore, (79 + 11x)/12 = (x + 1)
79 + 11x = 12x + 12
x = 79 12 = 67
Thus, average score after 12th inning = 67 + 1 = 68 runs.
9. Out of three numbers, the first is twice the second and is half of the third. If the average of the three numbers is 63, then difference of first and third numbers is:
a) 27
b) 50
c) 54
d) 48
Answer: C)
Explanation:  Let the second number be x
first number is twice the second, the first number = 2x
Also, since first number is half of the third, third number = 4x
Now, the average of the 3 numbers is 63.
We know that, average = Sum of all quantities/Number of quantities
(2x + x +4x)/3 = 63
7x =189
x = 27
Thus, the numbers are 54, 27 and 108
The difference of first and third number = 108 – 54 = 54
10. The average of 15 numbers is 35. If the mean of first 8 numbers is 33 and the mean of last 8 numbers is 37, what is the 8th number?
a) 31
b) 23
c) 35
d) 41
Answer: C)
Explanation: Average = Sum of observations/No. of observations
Sum of 15 numbers = Average × No.
Sum of 15 numbers = 35 × 15 = 525
Sum of first 8 numbers = 33 × 8 = 264
Sum of last 8 numbers = 37 × 8 = 296
Let the 8th number be x
x = (Sum of first 8 no. + Sum of last 8 no.) (Sum of 15 no.)
x = 264 + 296 525
x = 35