vin

Practice test #2 Section 3 Number 18
page 463

the answer explanation online isn't really clear on it... can anyone explain the problem and why the answer is A to me?

Avex

Ok, this is quite simple actually.
To state the obvious parts first:

x = amount of dollars 1st shirt
Since we have additional shirts, we have the x-z dollars.

x + (x-z)

Then, we know that n = amount of shirts
However, because of counting problems, we must place (n-1), in order to get the right [b]cost[b]. Therefore it must be:

x + (n-1)(x-z)

Think of it this way, if you are buying two shirts, you MUST put n-1, otherwise:

x + 2(x-z)

You would get the cost of 3 shirts. Remember that x represents the cost of the 1st shirt.

Hope that makes sense.

ThePeRfectscore

The answer is A