To calculate the mean or average, add all the data point up and whatever the amount of data point there are is supposed to be divided by the sum of the data points. So in this case, 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. This is the sum of the data points. Now we have to divide by the amount of data points which is 7 (0 obviously has no value whatsoever). 28 divided by 7 is 4. The average/mean of the number of post made is therefore 4.
A brownie costs $3.45, an ice cream costs $2.43, and a cookie costs $0.95. So $3.45 + $2.43 + $0.95 = $6.83. If you need to know the change if they paid with $10.00 also . . . That would be $10.00 - $6.83 = $3.17 change.
