Q1. The average marks of 50 students in a class is 72. The average marks of boys and girls in that subject are 70 and 75 respectively. The number of boys in the class is:
(a) 30
(b) 20
(c) 35
(d) 25
Q2. The average age of 14 girls and their teacher’s is 15. If teacher’s age is excluded the average reduces by 1. What is the teacher’s age?
(a) 35 years
(b) 32 years
(c) 30 years
(d) 29 years
Q3. There are 30 students in a class. The average age of first 10 students is 12.5 years. The average age of the remaining 20 students is 13.1 years. The average age (in years) of the students of the whole class is:
(a) 12.5 years
(b) 12.7 years
(c) 12.8 years
(d) 12.9 years
Q4. The average score of a class of boys and girls in an examination is A. The ratio of boys and girls in the class is 3 : 1. If the average score of the boys is A + 1, the average score of the girls is:
(a) A + 1
(b) A – 1
(c) A + 3
(d) A – 3
Q5. Five years ago, the average age of P and Q was 25. The average age of P, Q and R today is 25. Age of R after 5 years will be
(a) 15 years
(b) 20 years
(c) 40 years
(d) 35 years
Q6. The average of 20 numbers is 15 and the average of first five is 12. The average of the rest is:
(a) 16
(b) 15
(c) 14
(d) 13
Q7. The average monthly expenditure of a family is Rs. 2,200 during first three months. Rs. 2,550 during next four months and Rs. 3,120 during last five months of the years. If the total savings during the year was Rs. 1,260, what is the average monthly income?
(a) Rs. 1,260
(b) Rs. 1,280
(c) Rs. 2,805
(d) Rs. 2,850
Q8. The average salary of all the workers in a workshop is Rs. 8,000. The average salary of 7 technicians is Rs. 12,000 and the average salary of the rest is Rs. 6,000. The total number of workers in the workshop is:
(a) 20
(b) 21
(c) 22
(d) 23
Q9. The average age of 40 students of a class is 15 years. When 10 new students are admitted, the average is increased by 0.2 years. The average age of the new students is:
(a) 15.2 years
(b) 16 years
(c) 16.2 years
(d) 16.4 years
Q10. The average of 100 numbers is 44. The average of these 100 numbers and 4 others new numbers is 50. The average of the four new numbers will be:
(a) 800
(b) 200
(c) 176
(d) 24
Q11. The average of 30 numbers is 15. The average of the first 18 numbers is 10 and that of the next 11 number is 20. The last number is:
(a) 56
(b) 52
(c) 60
(d) 50
Q12. The average of 6 observations is 45.5. If one new observation is added to the previous observations, then the new average becomes 47. The new observation is
(a) 58
(b) 56
(c) 50
(d) 46
Q13. The present average age of a family of four members is 36 years. If the present age of the youngest member of the family be 12 years, the average age of the family at the birth of the youngest member was:
(a) 48 years
(b) 40 years
(c) 32 years
(d) 24 years
Q14. The average age of group of 20 girls is 15 years and that of another group of 25 boys it is 24 years. The average age of the two groups mixed together is:
(a) 19.5 years
(b) 20 years
(c) 21 years
(d) 21.5 years
Q15. A cricket batman had a certain average of runs for his 11 innings. In the 12th innings, he made a score of 90 runs and thereby his average of runs was decreased by 5. His average of runs after 12th innings:
(a) 155
(b) 150
(c) 145
(d) 140