Question

or
The mean of 100 items was found to be 64. Later on it was discovered
that two items misread as 26 and 9 instead of 36 and 90 respectively.
Find the correct mean.​

Answer 1

Answer:

64.91

Step-by-step explanation:

Total=Mean *no of Items=64*100=6400

Calculation Mistake

a =36-26=10

b =90-9=81

Number to be added =a+b=10+81=91

Current Total=6400+91=6491

New Mean =6491/100

=64.91

Answer 2

Answer:

sum of 100/100= 64

sum of 100= 6400

after the error was discovered it was found that

36 as 26- it was 10 less

90 as 9 - it was 81 less

real sum = 6400+10+81= 6491

real mean = 6491/100 = 64.91