Aptitude exam is the most important round, actually this is a get pass for the freshers to crack an interview. And in aptitude Mathematics is the important part. So if you want to practice these aptitude then either you have to buy a aptitude book or you can take admission in a coaching centre. One more way is there, that is search in internet, find questions and solve it. But I think this is more time taking. So I collect many questions with answer, you people can find the questions here in this site.
Today in this post I'm giving you some questions on Average chapter. So go for the bellow questions. And don't forget to share this site to your circle.
Some Rules:
1. Average = Sum of data / No. of data.
2. If the numbers are in A.P. (Arithmetic Progression), then the avg of numbers is given by
Avg = sum/n =[ (n/2)(a+l)]/n
= (a+l)/2
Where n – no. of quantities
a – first term or value
l – last term or value
3. Weighted Average:
Section1:
No. of quantities: m
Avg of section1: p
Section2:
No. of quantities: n
Avg of section1: q
Avg of section1 and section2 = (m*p + n*q)/(m +n)
Points to remember/Shortcuts
A> Average lies between minimum and maximum values.
a. Avg > minimum value
b. Avg < maximum value
B> If every quantity is increased/decreased by ‘k’ value, then the avg also get increased/decreased by the same ‘k’ value.
Questions and Answers:
Q. The average of 13 results is 40 and that of first six is 30 and last six is 34. Find the value of 7 th number.
Ans. 7 th number will be = Sum of 13 results - ( Sum of first six + Sum of last six ) = ( 13 * 40 ) - ( 6 * 30 + 6 * 34 ) = 136
Q. In a class, there are 20 students whose average age is decreased by two months, when one student aged 18 years is replaced by a new student, find the age of the new student ?
Ans. Age of new student = Age of removed student - Numbers of students * Decrease in average age
Age of new student = 18 - 20 * ( 2 / 12 ) = 44 / 3 = 14 years 8 months
Q. A man divides his total journey into three equal parts and decides to travel the three parts with speeds 60 km / hr , 24 km / hr and 45 km /hr . Find the average speed during the whole journey ?
Ans. speed = 3 * 60 * 24 * 45 / 60 * 24 + 24 * 45 + 45 * 60 = 37.24 km / hr.
Q. The mean temperature of Monday to Wednesday was 27 °C and of Tuesday to Thursday was 24 °C. If the temperature on Thursday was 2 / 3 rd of the temperature on Monday, What was the temperature on Thursday?
Ans. Mon + Tue + Wed = 81
Tue + Wed + Thu = 72
hence Mon - Thu = 9
Also Thu = ( 2 /3 ) * Mon
So the temperature of Thrusday = 18 °C
Q. A batsman makes a score of 70 runs in the 15 th innings and thus increases average by 2 runs. Find the average after 15 th innings?
Ans. Let the average after 15 th inning be x
The average after 14 th inning = (x-2)
Now 14 (x-2)+70=15x
So x=42
Q. The average age of a family of 8 members is 23 years. If the age of the youngest member be 7 years, then what was the average age of the family member at the birth of the youngest member?
Ans. Total age of all members= 8 * 23 =184 years
7, years ago, total sum of ages= 184 - ( 8 * 7 ) = 128 years
But 7 years before there were only 7 members in the family so,
Average at that time = 128/7 = 18.28 years.
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