Average sums with explanation

For those who are concentrating on the sums on average for the competitive exams, here is a fantastic answer!

Introduction:

If you want to be eligible to take the test in any field, aptitude is involved. As a result, developing your aptitude skills is important for job seekers. In this blog, we have given some of the aptitude questions to improve your knowledge.

The formulas which have been used in this sums are given in the previous blog

6. Of the four numbers, the first is twice the second, the second is one-third of the third and the third is 6 times the fourth. The average of the numbers is 13. The largest of these numbers is?

Answer: 24

Explanation:

Let the fourth number be a

Then, third number = 6a, second number = 2a and first number = 4a a + 4a + 2a + 6a = 13 * 4

13a = 13 * 4

a = 4

The numbers are 4, 24, 8 and 16

The largest of these numbers are 24.

7. The average age of 30 boys of a class is equal to 13 years. When the age of the class teacher is included the average becomes 15 years. Find the age of the class teacher?

Answer: 75 years

Explanation:

Total ages of 30 boys = 13 * 30

= 390 years

Total age when teacher is included = 15 * 31

= 465 years

Age of class teacher = 465 - 390

= 75 years

Age of class teacher = 75 years.

8. The Average of marks obtained by 120 candidates in a certain examination is 35. If the average marks of passed candidates is 35 and that of failed candidates is 15, what is the number of candidates who passed the examination?

Answer: 120

Explanation:

Let the number of passed candidates be a

Then, total marks = 120 * 35 = 35a + (120 - a) * 15 4200 = 35a + 1800 - 15a

2400 = 20a

a = 120

The number of passed candidates is 120.

9. The captain of a cricket team of 11 members is 28 years old and the wicket keeper is 3 years older. If the ages of these two are excluded, the average age of the remaining players is one year less than the average age of the whole team. What is the average age of the team?

Answer: 25 years

Explanation:

Let the average age of the whole team be x years

Given data, the age of captain of a cricket team = 28 years If the wicket keeper is 3 years older,

Then, the age of wicket keeper = 28 + 3 = 31

If the ages of these two are excluded, the average age of the remaining players is one year less than the average age of the whole team,

Then, new average ? [11x - (28 + 31)] / 9 = x - 1 [ 11x - 59] / 9 = x - 1

(11x - 59) = 9 (x - 1) (11x - 59) = 9x - 9 11x - 9x = 59 - 9

2x = 50

x = 25

The average age of the whole team is 25 years.

10. Out of 9 persons, 8 persons spent Rs. 40 each for their meals. The ninth one spent Rs. 30 more than the average expenditure of all the nine. The total money spent by all of them was?

Answer: Rs. 393.75

Explanation:

Let the average expenditure be Rs. x x = [(8 * 40) + (30 + x)] / 9

9 * x = [(8 * 40) + (30 + x)]

9x = 320 + 30 + x

9x = 350 + x

9x - x = 350

8x = 350

x = 350 / 8

x = 43.75

The total money spent by all of them = 9x [ Total persons - 9]

= 9 * 43.75

= Rs. 393.75

The total money spent by all of them was Rs. 393.75.

Conclusion

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