Guruji Classes -start…learning

you’re on the right track now

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