Question

The A.M of 10 numbers is 7. The A.M of 15 numbers is 12, then the mean of all observations is

Answer 1

X/10=7. Y/15=12. Thus X=70 and Y=180. X denotes the sum of first series of numbers. Y denotes the sum of second series of numbers. Mean of all numbers=(X+Y)/total numbers. =(70+180)/(10+15)=10. Thus the answer is 10.

Answer 2

Step-by-step explanation:

x/10=7 and Y/15=12

x=70 Y=180

m= X+Y/Total number

m=70+180/10+15

m=250/25

m=10