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Q17. In an examination, the average of marks was found to be 50.
For deducting marks for computational errors, the marks of 100
candidates had to be changed from 90 to 60 each and so the average
of marks came down to 45. The total number of candidates,
who appeared at the examination, was
a) 600
b) 300
c) 200
d) 150
Q18. a, b, c, d, e, f, g are consecutive even numbers.
j, k, l, m, n are consecutive odd numbers. The average
of all the numbers is
a) 3 ((a+n)/2)
b) 3((l+d)/2)
c) ((a+b+m+n)/4)
d) (j+c+n+g)/4
Q19. The average of n numbers x1, x2, ……xn is x ¯.
Then the value of ?n_(i=1)?? (x?_i- x ¯ ?) is equal to
a) n
b) 0
c) n x ¯
d) x ¯
Q20. B was born when A was 4 years 7 months old and C was
born when B was 3 years 4 months old. When C was 5 years
2 months old, then their average age was
a) 8 years 9 months
b) 7 years 3 months
c) 8 years 7 months
d) 8 years 11 months
Q21. In the afternoon, a student read 100 pages per hour.
What was her average rate of reading, in pages per hour?
a) 60
b) 70
c) 48
d) 50
Q22. Ram aims to score an average half yearly exam.
But his average in quarterly is 3 marks less than his
target and that in half yearly is 2 marks more between
the total marks scored in both the exams is 25. Total marks aimed by Ram are:
a) 400
b) 410
c) 420
d) 380
Q23. In an exam, the average marks obtained by the students
was found to be 60. After omission of computational errors,
the average marks of some 100 candidates had to be changed
from 60 to 30 and the average with respect to all
the examinees came down to 45 marks. The total number of candidates who took the exam was
a) 200
b) 210
c) 240
d) 180
Q24. If the average of x and 1/x (x?0) is M,
then the average of x^2 and 1/x^2 is
a) 1- M2
b) 1- 2 M
c) 2 M2– 1
d) 2 M2+1
Answers
17 a 18 b 19 b 20 d 21 c 22 a 23 a 24 c
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