SOLUTION: A deli is offering a special for its sandwiches. A customer will receive three free sandwiches for every five sandwiches purchased. Jane ordered 609 sandwiches for an office party

For every 8 sandwiches Jane ordered, she paid for 5 and got 3 free.
So we need to know how many groups of 8 sandwiches she ordered:

                   76
                8)609
                  56
                   49
                   48
                    1

So she ordered 76 groups of 8 sandwiches, and 1 sandwich left over 
(the remainder from the division above)

So she paid for 76×5 or 380 sandwiches plus she had to pay for the 
one extra sandwich left over.  That's 380+1 she had to pay for.

Answer: 381 

Edwin