Question

of a set of 30 numbers, average of first 10 numbers = average of last 20 numbers. then the sum of the last 20 numbers is? options : a) 2 x sum of last ten numbers b) 2 x sum of first ten numbers c) sum of first ten numbers d) cannot be determined with given data

Answer 1

As per formula of mean,
$\frac{sum \: of \: first \: 10 \: nos}{10} = \frac{sum \: oflast \: 20 \: nos}{20} \\ so \\ sum \: of \: last \: 20 \: nos = 2 \times sum \: of \: first \: 10 \: nos$
Hope this helps