Maths chapter average lecture 1 for all competitive exams

A national math examination has 4 statics problems. The distribution of the number of students who ansered the question correctly is shown in the chart. If 400 students took the exam and each question was worth 25 points, then what is the average score of the students taking the exam? {:("Question Number","Number of students who solved the question"),(1,200),(2,304),(3,350),(4,250):}

Susan received grades of 78, 93, 82, and 76 on four math exams. What is the lowest score she can receive on her next math exam and have an average of at least 85 on the five exams?

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

In a class, 18 students had an average midterm exam grade of 85 and the 12 remaining students had an average midterm exam grade of 90. What is the average midterm exam grade of the entire class?

The average speed of all the molecules in a gas at a given instant is not zero, whereas the average velocity of all the molecules is xero. Explain why ?

Twelve friends raised some funds among themseleve for a dinner party. Ten of the contributed $80 each while the other two subscrible $80 and $120 more than the average of all twelve friends . What was the average contribution of all the friends taken together ?

Assertion (A) . Energy of resonance hybrid is equal to the average of energines of all canonical forms. Reason (R). Resonance hybrid cannot be presented by a single structure.

For any arbitrary motion in space, which of the following relations are true? a) v_("average") = (1//2)(v(t_(1) + v(t_(2)) b) v_("average") = [r(t_(2))-r(t_(1)]/(t_(2)-t_(1) v(t) = v(0) + at d) a_("average") = [v(t_(2))-v(t_(1))/[t_(2)-t_(1)) The average stands for average of the quantity over time interval t_(1) to t_(2)

Abdul while driving to school, computes the average speed for his trip to be 20 kmh^(-1) . On his return trip along the same route, there is less traffic and the average speed is 40 kmh^(-1) . What is the average speed for Abdul's trip ?

Abdul, while driving to school, computes the average speed for his trip to be 20 km h^(-1) . On his return trip along the same route, there is less traffic and the average speed is 30 km h^(-1) . What is the average speed for Abdul's trip ?