You can put this solution on YOUR website! consider this..... if two numbers have an average of 10 then the sum total of those 2 numbers must be 20 (i.e. 2 times 10). This is because the average is the total divided by the number of values.
If 3 numbers had an average of 15 the total of those 3 numbers must be 45 (i.e. 3 times 15).
So, if the average of 25 numbers is 20 then the total of those numbers must be 20 times 25 = 500.
