Acollege student earned $246, $288, $234, and $276 over a four-week period. how much must he earn during the fifth week to have average earnings of $255 for the five weeks?

We calculate average by adding up all the data and dividing it by the total number of entries.

Start off by first making an equation like so:

= 255, where X = the earnings for the fifth week.

Now multiply both sides by the denominator (5) to get this:

246+288+234+276+X = 1,275

Add up all the known earnings so far:

1,044 + X = 1,275

Subtract the total earnings so far from both sides:

X = 231

231

The answer is part a: use