Trey has scored 21, 19, 29, and 23 points in his four basketball games so far. How many points does he need to score in his next game so that his average (mean) is 22 points per game?

Question

ranga · Answer

Assume x to be the score in the next game.
What will be the average of 5 games if the scores are: 21, 19, 29, 23 and x   ?

anonymous · Answer

22

ranga · Answer

We want the average to be 22.  
But what is the formula for finding the average of 21, 19, 29, 23 and x   ?

anonymous · Answer

Add then divide by the number of values

ranga · Answer

Exactly. 
Add the 5 numbers divide by 5   and equate it to 22.  Solve for x.

anonymous · Answer

So then what is x?

ranga · Answer

(21 + 19 + 29 + 23 + x) / 5  =  22
simplify:
(92 + x) / 5 = 22
To solve for x, isolate x.
multiply both sides by 5.
subtract 92 from both sides to find x.