If you would like to know which one of the options is better to buy, you can calculate this using the following steps:
3 sandwiches ... $4.95
1 sandwich ... $x = ?
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3 * x = 1 * 4.95 /3
x = 4.95 / 3 = $1.65
4 sandwiches ... $6.72
1 sandwich ... $y = ?
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4 * y = 1 * 6.72 /4
y = 6.72 / 4 = $1.68
Result: You should buy sandwiches from the first option ($1.65 < $1.68 per unit).
