Big family

A certain number of people met at the family celebration - their average age was three times the number present. Then came my grandfather, who was 75 years old, and the average age was again three times the number present. How many people are celebrating right now?

Correct answer:

n =  13

Step-by-step explanation:

3(n1) = s/(n1) 3n = (s+75)/n  3n26n+3 = s 3n2 = s+75   3n2 = (3n26n+3)+75  0 = 6n+3+75  0=6 n+3+75  6n=78  n=678=13  n=13   Verifying Solution:  s=3 n275=3 13275=432 a1=s/(n1)=432/(131)=36 A1=3 (n1)=3 (131)=36 a2=(s+75)/n=(432+75)/13=39 A2=3 n=3 13=39

Did you find an error or inaccuracy? Feel free to write us. Thank you!

Tips for related online calculators
Looking for help with calculating arithmetic mean?
Looking for a statistical calculator?
Are you looking for help with calculating roots of a quadratic equation?
Do you have a linear equation or system of equations and looking for its solution? Or do you have a quadratic equation?

You need to know the following knowledge to solve this word math problem:

We encourage you to watch this tutorial video on this math problem: video1

Related math problems and questions: