Answer:
3 sandwiches for $15.00 is the better value
Explanation:
3 sandwiches for $15.00
3s = $15.00
Divide by 3 on both sides
s = $5.00
This means that you are getting each sandwich for $5.00
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4 sandwiches for $21.00
4s = $21.00
Divide by 4 on both sides
s = $5.25
This means that you are getting each sandwich for $5.25
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$5.00 < $5.25
3 sandwiches for $15.00 is a better deal because you pay $0.25 less per sandwich.
Hope this helps :)