Question

Effect of 30 numbers average of first 10 number is equal to average of last 20 numbers

Answer 1

2xsum of first ten numbers
sum of first 10 numbers be a
sum of last 20 numbers be b
avg of first 10 nos =avg of last 20 nos
i.e (a/10)=(b/20)
(20 x a)/10 = b
2a=b
therefore 2 x sum of first ten numbers = sum of last 20 numbers