The average of six numbers is 22. The numbers are 20,17,18,24,29 and x. Find x

The answer is 24. Because there are 6 number in the set (including x) the product of the avg. (22) and the amount of numbers (6) should equal what the total of the sum of number, so you should end up with an equation like this: x+20+17+18+24+29=132. If you combine the like terms you get: x+108=132. Subtract 132 from both sides to make the equation equal to x and you get x=24