Question

find the mean of 30 number given mean of ten of them is 12 and the mean of the remaining is 20 is 9

Answer 1

given is that 30 number
than 10 no of mean is 12
total no/10 =12
total no sum =12×10=120
remaining 20 no of mean is 9
total no/20 =9
total no sum =20×9 =180
total no of sum =120+180 =300
so mean of 30 no is
300/30 =10