After replacing an old member by a new member, it was found that the average age of five members of a club is the same as it was 3 years ago. What is the difference between the ages of the old and the new member?
সমাধান
সঠিক উত্তর: Option A
z= New member
x=old member
4 member+ x member=sum
4 member+ 12+z=sum
x=12+z
x+3=15+z
(x+3)-z=15
