The arithmetic mean of 100 observations is 24. if 6 is added to each of the observations and then each of them is multiplied by 2.5, find the new arithmetic mean.

The arithmetic mean = Sum of all observations/Number of observations

Hence, sum of all observations = 24*100 = 2400

 

Now, 6 is added to each of the observations, so the sum would be 2400 + 100*6 = 3000

And then, each of them is multiplied by 2.5. So, the new sum of all observations = 3000*2.5 =7500

 

Hence mean - 7500/100 = 75