The average of some natural numbers is 15. If 30 is added to first number and 5

Check All Courses

Question

The average of some natural numbers is 15. If 30 is added to first number and 5 is subtracted from the last number the average becomes 17.5 then the number of natural number is

Options:

A . 20

B . 10

C . 30

D . 15

Answer: Option B
Answer: (b)Number of natural numbers = x ∴ Their sum = 15x According to the question, 15x + 30 – 5 = x × 17.5 ⇒ 17.5x – 15x = 25 ⇒ 2.5x = 25 ⇒ x = $25/2.5$ = 10

Was this answer helpful ?

Next Question

Submit Comment/FeedBack

More Questions on This Topic :

Question 1. There are two groups A and B of a class, consisting of 42 and 28 students respectively. If the average weight of group A....40 kg, find the average weight of the whole class.

Question 2. The average income of 40 persons is Rs. 4200 and that of another 35 persons is Rs. 4000. The average income of the whole....4000. The average income of the whole group is :

Question 3. The average weight of 3 men A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If ano....and E becomes 79 kg. Then weight of A is

Question 4. The average of 1, 3, 5, 7, 9, 11, -------- to 25 terms is....

Question 5. The average of 30 results is 20 and the average of other 20 results is 30. What is the average of all the results ?....

Question 6. If average of 20 observations $x_1 , x_2 , ....., x_20$ is y, then the average of $x_1 – 101, x_2 – 101, x_3 – 101....x_2 – 101, x_3 – 101, ....., x_20 –101$ is

Question 7. The average weight of 8 persons increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. The ....weighing 65 kg. The weight of the new person is

Question 8. The average of marks obtained by 100 candidates in a certain examination is 30. If the average marks of passed candidate....what is the number of candidates who passed the examination?

Question 9. The average of 30 numbers is 15. The average of the first 18 numbers is 10 and that of the next 11 numbers is 20. The la....the next 11 numbers is 20. The last number is

Question 10. The average of 20 numbers is 15 and the average of first five is 12. The average of the rest is....

Latest Videos

Chapter 1 - GLOBAL STEEL SCENARIO & INDI Part 1 : (13-04-2024) INDUSTRY AND COMPANY AWARENESS (ICA)

Direction Sense Test Part 1 Reasoning (Hindi)

Chapter 1 - RMHP / OHP / OB & BP Part 1 : (14-02-2024) GPOE

Cube & Cuboid Part 1 Reasoning (Hindi)

Data Interpretation (DI) Basic Concept Reasoning (Hindi)

Counting Figures Part 1 Counting Of Straight Lines Reasoning (Hindi)

Sail E0 free webinar Webinars

Real Numbers Part 7 Class 10 Maths

Real Numbers Part 1 Class 10 Maths

Polynomials Part 1 Class 10 Maths

Latest Test Papers

Chapter 3.1 : Overview of Finance & Acco Chapter 3 : Finance & Accounts SAIL E0 - GFM 2024

Chapter 2.1 : Overview Chapter 2 : Materials Management SAIL E0 - GFM 2024

Chapter 1.1 : Personnel Functions- An ov Chapter 1 : Personnel Management SAIL E0 - GFM 2024

GPOE / GPA Combined 1 Free CBT Mock Test SAIL E0 2024

CBT Mixed Test 1 GPOE/GPA SAIL E0 2024