Question

22. the average of 10 numbers is 30. it is later found that 2 numbers have been wrongly added. the first number added is 10 more than the actual number and the second number added is 25 instead of 50. what is new average?

Answer 1

1. Given (x1+x2+......+x10)/10=30 i.e, (x1+x2+......+x10)=300
2. Also givenit is later found that 2 numbers have been wrongly added. the first number added is 10 more than the actual number and the second number added is 25 instead of 50 hence original numbers r as follows
3. (x1-10)+(x2+25)+x3+......+x10=300
4. (x1+x2+......+x10)=275 which can be written as (x1+x2+......+x10)=27.5*10
5. i.e,(x1+x2+......+x10)/10=27.5 which is new average