Averages Assignment 3

The average salary of all the workers in a workshop is Rs.8000. The average salary of 7 technicians is Rs.12000 and the average salary of the rest is Rs.6000. The total number of workers in the workshop is:

• 21

• 14

• 7

• 20

40% of the employees in a factory are workers. All the remaining employees are executives. The annual income of each worker is Rs. 390. The annual income of each executive is Rs. 420. What is the average annual income of all the employees in the factory together?

• Rs. 400

• Rs. 405

• Rs. 410

• Rs. 408

 The average age of a class is 15.8 years. The average age of the boys in the class is 16.4 yrs while that of the girls is 15.4 years. What is the ratio of boys to girls in the class?

• 3:5

• 4:5

• 5:4

• 2:3

A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is

• 300

• 285

• 315

• 420

If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is:

• 53.23

• 54.69

• 55.23

• 56.69

The total age of the class of 75 girls is 1050 years, the average age of 25 of them is 12 years and that of another 25 is 16 years. Find the average age of the remaining girls?

• 14

• 15

• 16

• 17

The difference between two angles of a triangle is 24°. The average of the same two angles is 54°.What is the value of the greatest angle of the triangle?

• 72

• 66

• 108

• 42

A student finds the average of 10 positive integers. Each integer contains two digits. By mistake, the boy interchanges the digits of one number, say ba for ab. Due to this, the average becomes 1.8 less than the previous one. What was the difference between the two digits a and b?

• 4

• 3

• 2

• 8

 A motorist travels to a place 150 km away at an average speed of 50 km per hour and returns at 30 km per hour. His average speed for the whole journey in km per hour is :

• 35

• 40

• 45

• 37.5

In a class of 60 students, the average marks of the first 45 students is 80, while the average marks of the remaining 15 students is 90. What is the average mark of the entire class?

• 85

• 82.5

• 87.5

• 88