Jessica ate 209 snack packs last year. Snack packs are sold in boxes of ten or as singles. Fill in the chart below with 3 possible combinations of snack packs that Jessica could have bought last year.

Answer 1

boxes of 10 singles

20 9

19 19

18 29

17 39

16 49

15 59

14 69

13 79

12 89

11 99

10 109

9 119

8 129

7 139

6 149

5 159

4 169

3 179

2 189

1 199

0 209

each row sums to 209

or if she bought 21 packs she'd have 1 snack left over for the next year

but it would probably be the cheapest way to go, depending on the relative prices of the 10 pack and the single pack.

Usually, almost always there's a volume discount. if the 10 pack cost less than $10 and the single snack cost $1, it would be cheaper to buy 21 ten packs.

21 x $9.99 = $209.79 for 21 ten packs

20 x $9.99= $199.80 plus one single at $1 = $209.80 saving one penny by buying 21 ten packs instead of 20 tens and 1 single, if there's a once cent volume discount.