Question 973575
say you want 250g of peanut butter, you could
buy one 250g jar of peanut butter for $6.50 or
you would have to buy three 100g jars of peanut butter at $3.10 per jar,
3 * $3.10 = $9.30
therefore, buying one jar at $6.50 saves you
$9.30 - $6.50 = $2.80
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we can calculate the price per gram of peanut butter for each jar type
1) $6.50 / 250 = $0.026 
2) $3.10 / 100 = $0.031
therefore the $6.50 for a 250g jar is cheaper