Averages Questions For Railway/RRB Group-D PDF:-
Download Averages Questions For RRB Group-D PDF with detailed solutions. Important Practice Average questions based on previous year railway RRB exam papers.
Download Averages Questions For RRB Group-D PDF
Get 20 RRB Group-D Mocks for just Rs. 99
Also download Railway group-D topic wise mcq’s PDF
Question 1: 35 is the average marks obtained by 120 students. The average marks of successful candidates was 39 and that of unsuccessful candidates was 15. What is the number of successful candidates in that examination ?
a) 100
b) 110
c) 120
d) 80
Question 2: 45 is the average marks obtained by 30 students of a class. On checking, two errors were identified. On correction, one student obtained 45 more marks while other obtained 15 less marks. What is the average of corrected marks ?
a) 45
b) 44
c) 47
d) 46
Question 3: 5 years ago, average age of P and Q was 15 years. At present, average age of P, Q and R is 20 years. What will be the average age after 10 years ?
a) 35 years
b) 40 years
c) 30 years
d) 50 years
Question 4: The average height of 35 students in a class is 4’2”. Three students of average height moved to new section while 6 students of total height 33’4” joined the class The average height of the student in the class is now
a) 4’6”
b) 5’
c) 4’4”
d) 4’8”
Question 5: A man worked 14 hours a day for the first 2 days, 12 hours a day for the next 3 days but did not work on the sixth day. Then on the average how much did he work in the first six days ?
a) 10 hours 4 minutes
b) 9 hours 40 minutes
c) 10 hours 40 minutes
d) 15 hours 40 minutes
Take free RRB Group-D mock test
Answers & Solutions:
1) Answer (A)
Let there be x successful candidates in the exam.
Unsuccessful candidates = 120 – x
Total score = 35 x 120
Total score is also equal to x * 39 + (120 – x) * 15
So, x = (35 * 120 – 120 * 15)/ 24 = 120 * 20 / 24 = 100
2) Answer (D)
On correction, total increase in marks = 45 – 15 = 30 marks.
Number of students = 30
So, increase in the average = 30/30 = 1 mark.
3) Answer (C)
The average age increases with age. So, after 10 years, the average age is 20 + 10 = 30 years.
4) Answer (C)
After the students left, there will be 32 students with the same average height. 4 ft and 2 inches
Total height = 32 x 4.17 = 133.44
Total height of 6 students is 33 ft and 4 inches. = 33.33
New total height = 133.44 + 33.33 = 166.77
New average height = 166.77/ 38 = 4 feet 4 inches
5) Answer (C)
Total number of hours worked by the man = 14 x 2 + 12 x 3 = 64 hours
So, the average in 6 days = 64/6 = 10 hours and 40 mins
