Aptitude ➤ Averages ➤ Set 1

#### Averages : Important Facts and Formulae

Average:
Average = Sum of observations / Number of observations

Average Speed :
Suppose a man covers a certain distance at x kmph and an equal distance at y kmph.
Then, the average speed druing the whole journey is [2xy/(x+y)] kmph.
Question 16
Q16.  The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that B and C be 43 kg, then the weight (in kg) of B is :
Question 17
Q17.  The average weight of 15 oarsmen in a boat is increased by 1.6 kg when one of the crew, who weights 42 kg is replaced by a new man. Find the weight of the new man (in kg).
Question 18
Q18.  Three Science classes A, B and C take a Life Science test. The average score of class A is 83. The average score of class B is 76. The average score of class C is 85. The average score of class A and B is 79 and average score of class B and C is 81. Then the average score of classes A, B and C is :
Question 19
Q19.  The average monthly salary of all the employees in an industry is Rs 12000. The average salary of male employees is Rs 15000 and that of female employees is Rs 8000, what is the ratio of male employees to female employees.
Question 20
Q20.  Out of four numbers the average of the first three is 16 and that of the last three is 15. If the last number is 20 then the first number is