Two mail order book clubs offer discount prices....

Question

the first club charges $35 for membership and $4 per book. the second club has a $5 membership and charges $7.50 per book for what number of books is the cost the same?

Answer 1

The trick to this Halloween treat is to realize that we need to find an equation for the each pricing plan and set them equal.

 

The first pricing equation is:

 

Price of plan 1 = $35 + number of books*$4

Price of plan 2 = $5   + number of books*$7.5

Setting the price of plan 1 equal to Price of plan 2 yields

$35 + number of books*$4 = $5 + number of books*$7.5; solving for number of books yields

$35-$5= number of books *(7.5-4)

$30 = number of books *(3.5)

$30÷ 3.5 = number of books

8.5714 = number of books where cost is the same.