Average – Set 8

1) Average of 80 numbers are 42. When 5 more numbers are included, the average of 85 numbers become 45. Find the average of 5 numbers ?

2) Find the average of first 97 natural numbers?

3) Five year ago, the average age of A,B,C and D was 45yr.with E joining them now,the average of all the five is 49yr. How old is E?

4) A batsman makes a score of 270 runs in the 87th inning and thus increase his average by a certain number of runs that is a whole number. Find the possible values of the new average ?

5) A train covers the first 16km at a speed of 20km per hour another 20km at 40km per hour and the last 10km at 15km per hour. Find the average speed for the entire journey ?

6) The average monthly salary of 660 workers in a factory is Rs.380. The average monthly salary of officers is Rs.2100 and the average monthly salary of the other workers is Rs.340. Find the number of the other workers?

7) A man travels equal distances of his journey at 40,30 and 25km/h. respectively. Find his average speed for whole journey ?

8) The speed of the train going from Kathmandu to Dhangadhi is 100km/h while when coming back from Dhangadhi to Kathmandu, it’s speed 150km/h. Find the average speed during whole journey ?

9) The average of the first five multiples of 9 is?

10) The average of a group of men is increased by 5 years when a person aged of 18 years is replaced by a new person of aged 38 years. How many men are there in the group?

11) Ajit has a certain average for 9 innings. In the tenth innings, he scores 100 runs thereby increasing his average by 8 runs. His new average is?

12) The average of 25 results is 18. The average of first 12 of those is 14 and the average of last 12 is 17. What is the 13th result?

13) In a boat there are 8 men whose average weight is increased by 1kg when 1 man of 60kg is replaced by a new man. What is weight of new comer?

14) The average marks of four subjects is 120. If 33 was misread as 13 during the calculation, what will be the correct average ?

15) The average temperature for wednesday, Thursday and Friday was 40°C. The average for Thursday,Friday and Saturday was 41°C. If temperature on Saturday was 42°C,what was the temperature on Wednesday?

16) Students of three different classes appeared in common examination. Pass average of 10 students of first class was 70%, pass average of 15 students of second class was 60% and pass average of 25 students of third class was 80% then what will be the pass average of all students of three classes ?

17) Find the average increase rate, if increase in the population in the first year is 30% and that in the second year 40%?

18) The average age of three boys is 15 years. If their ages are in ratio 3:5:7, the age of the youngest boy is?