The average age of the members of a club increases to 27 when 3 more persons whose average age is 29 join them from 26. What is the number of members in the club now?

I did not understand this question at all. I will be really greatful if I get an explanatory answer

Total 6 person before adding 3 more person.
Solution:
Total age of x person = 26x
Add 3 person with avg age 29
i.e total age of x+3 person = 26x +29*3

Given after adding 3 person avg age is 27.
Total age = 27*(x+3)

Now solve the equation
26x+29*3=27*(x+3)

Ans 6
Total person 6+3=9

initial avg weight is 26

average weight if the added 3 persons is 29

avg weight after addition of 3 members is 27

let the initial number be X so their total weight will be X * 27

so  ((X*27)+(3*29))/(X+3)=27

X will be 6 so answer is 9