Average Questions Answers (MCQ) listings with explanations includes calculating average in different type of questions a which are important for many competitive exams.

11) The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband

• 1) 40
• 2) 35
• 3) 45
• 4) 55
Ans.   A
Explanation :
Sum of the present ages of husband, wife and child = (27 * 3 + 3 * 3) years = 90 years. Sum of the present ages of wife and child = (20 * 2 + 5 * 2) years = 50 years. Husband's present age = (90 - 50) years = 40 years

12) The average of six numbers is X and the average of three of these is Y.If the average of the remaining three is z, t

• 1) x = y + z
• 2) 2x = y + z
• 3) x = 2y + z
• 4) x = y + 2z
Ans.   B
Explanation :
X =((3y+3z)/6) or 2X= y + z

13) A motorist travel to a place 150 km away at an avearge speed of 50 km/hr and returns ar 30 km/hr.His average speed for the whole jouney in km/hr

• 1) 36.5 km/hr
• 2) 37.5 km/hr
• 3) 35.5 km/hr
• 4) 34.5 km/hr
Ans.   B
Explanation :
Average speed will be \begin{aligned} \frac{2xy}{x+y} km/hr \end{aligned} = \frac{2(50)(30)}{50+30} km/hr = 37.5 km/hr

14) The average age of the mother and her six children is 12 years which is reduced by 5 years if the age of the mother is excluded. How old is the mot

• 1) 40
• 2) 41
• 3) 42
• 4) 43
Ans.   C
Explanation :

15) The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher

• 1) 45
• 2) 50
• 3) 55
• 4) 60
Ans.   A
Explanation :

16) Average of first five multiples of 3

• 1) 9
• 2) 11
• 3) 13
• 4) 15
Ans.   A
Explanation :
\begin{aligned} Average = \frac{3(1+2+3+4+5)}{5} = \frac{45}{5} = 9 \end{aligned}

17) Average age of boys in a class is 16 years and average age of girls is 15 years, what is the average age of a

• 1) 15.5
• 2) 15
• 3) 16
• 4) Cant be computed
Ans.   D
Explanation :
As number of girls and boys is not given so result cant be computed

18) A library has an average of 510 visitors on Sundays and 240 on other day. The average number of visitors in a month of 30 days starting with sunday

• 1) 280
• 2) 285
• 3) 290
• 4) 295
Ans.   B
Explanation :
As the month begin with sunday, so there will be five sundays in the month. So result will be: \begin{aligned} = (\frac{510 \times 5 + 240 \times 25}{30}) = (\frac{8550}{30}) = 285 \end{aligned}

19) A batsman makes a score of 87 runs in the 17th match and thus increases his average by 3. Find his average after 17th ma

• 1) 36
• 2) 37
• 3) 38
• 4) 39
Ans.   D
Explanation :
Let the average after 17th match is x then the average before 17th match is x-3 so 16(x-3) + 87 = 17x => x = 87 - 48 = 39

20) Average weight of 10 people increased by 1.5 kg when one person of 45 kg is replaced by a new man. Then weight of the new man

• 1) 50
• 2) 55
• 3) 60
• 4) 65