Investigate!

Your neighborhood grocery store has a candy machine full of Skittles.

  1. Suppose that the candy machine currently holds exactly 650 Skittles, and every time someone inserts a quarter, exactly 7 Skittles come out of the machine.

    1. How many Skittles will be left in the machine after 20 quarters have been inserted?

    2. Will there ever be exactly zero Skittles left in the machine? Explain.

  2. What if the candy machine gives 7 Skittles to the first customer who put in a quarter, 10 to the second, 13 to the third, 16 to the fourth, etc. How many Skittles has the machine given out after 20 quarters are put into the machine?

  3. Now, what if the machine gives 4 Skittles to the first customer, 7 to the second, 12 to the third, 19 to the fourth, etc. How many Skittles has the machine given out after 20 quarters are put into the machine?

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