LIVE Course for free

Rated by 1 million+ students
Get app now
JEE MAIN 2023
JEE MAIN 2023 TEST SERIES
NEET 2023 TEST SERIES
NEET 2023
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
115 views
in Mathematics by (59.9k points)
closed by
The average age of a group of persons going on a trip is 16.75 years. 20 new persons with an average age of 13.25 years join the group on the spot due to which the average of the group becomes 15 yrs. find the number of persons initially going for the trip.
1. 21
2. 24
3. 20
4. 28

1 Answer

0 votes
by (110k points)
selected by
 
Best answer
Correct Answer - Option 3 : 20

Given:

Initial average = 16.75 years.

20 new persons with an average age of 13.25 years joined

New average = 15 yrs.

Formula:

Average of n numbers a1, a2, ………. an = (a1 + a2 + ... + an)/n

Calculation:

Let the no. of person initially going for the trip be x.

Total age of x persons = x × 16.75

Total age of 20 persons = 13.25 × 20 = 265

Total age of all the persons = 15 × (x + 20)

From the question

16.75x + 265 = 15(x + 20)

⇒ 16.75x + 265 = 15x + 300

⇒ 1.75x = 35

⇒ x = 20

∴ Initial number of person is 20

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...