Question 526363
The way you would do this problem is:
Find the sum of the first three numbers (x) then find the sum of the next 7 numbers (y), add these two sums together (x+y) and divide the lot by the total number of numbers, which is 10, ({{{(x+y)/10}}}).
{{{x/3 = 9}}} Multiply both sides by 3.
{{{x = 27}}}
{{{y/7 = 30}}} Multiply both sides by 7.
{{{y = 210}}}.
{{{(x+y)/10 = 237/10}}}={{{23.7}}}