1. The average salary of 12 officers
in a factory is Rs. 3950 per
month and that of other employees of the factory is Rs. 1850 per
month. If the average salary of
all employees (including the
officers) of the factory be Rs.
2150 per month, find the total
number of employees in the
factory.
(1) 80 (2) 85
(3) 84 (4) 86
2. In a class there are 40 boys and
their average age is 16 years. One
boy aged 17 years leaves the
school and another joins, and
their average age becomes 15.95
years. What is the age of the new
boy ?
(1) 14 years (2) 15 years
(3) 16 years (4) 18 years
3. The average weight of 29 students
is 40 kg. If the weight of teacher
be included, the average weight
is increased by 300 gms. The
weight of the teacher is :
(1) 49 kg (2) 56 kg
(3) 58 kg (4) None of these
4. The difference between the ages
of two sisters is half the
difference between the ages of
their parents. The elder sister is
18 years of age. Their father’s age
was 32 years when the younger
sister was born who is now 15
years old. What is their mother’s
age?
(1) 40 (2) 41
(3) 42 (4) 43
5. The average of five results is 46
and that of first four is 45. Find
the value of the fifth result.
(1) 50 (2) 60
(3) 45 (4) 40
6. Out of three numbers, the first
is twice of the second and is half
of the third. If the average of three
numbers is 56, find the largest
number.
(1) 50 (2) 48
(3) 96 (4) 75
7. The average of three numbers
is 42. The first is twice the second and the second is twice the
third. What is the difference between the largest and the smallest number?
(1) 50 (2) 46
(3) 48 (4) 54
8. The average age of three boys is
15 years. If their ages are in the
ratio 3 : 5 : 7, what is the age of
the youngest boy?
(1) 9 years
(2) 8 years
(3) 8 years 3 months
(4) None of these
9. a, b, c, d and e are five consecutive odd numbers. What is their
average?
(1) a + 2 (2) a + 4
(3) a + 3 (4) a + 1
10. The average height of 30 girls out
of a class of 40 is 160 cms and
that of the remaining girls is 156
cms. What is the average height
of the whole class?
(1) 155cm (2) 157 cm
(3) 159 cm (4) None of these
11. The average of 50 numbers is 38.
If two numbers, namely 45 and
55 are discarded, what is the average of the remaining numbers?
(1) 38.5 (2) 36.5
(3) 35.5 (4) 37.5
12. The average of 25 results is 18;
that of first twelve is 14 and of
last twelve is 17. Find the thirteenth result.
(1) 68 (2) 78
(3) 79 (4) 87
13. The average of ten numbers is
calculated as 15. It was discovered later on that while calculating the average one number
namely 36 was wrongly read as
26. Find the correct average.
(1) 16 (2) 18
(3) 19 (4) 16.5
14. Out of four numbers, the average of first three is 15 and that
of last three is 16. If the last number is 19, find the first number.
(1) 14 (2) 15
(3) 16 (4) 18
15. The average of 6 observations is
12. A new seventh observation
is included and the new average
is decreased by 1. Find the seventh observation.
(1) 5 (2) 7
(3) 8 (4) 9
answer:1. (3) 2. (2) 3. (1) 4. (2)
5. (1) 6. (3) 7. (4) 8. (1)
9. (2) 10. (3) 11. (4) 12. (2)
13. (1) 14. (3) 15. (1
