Question 1014332
the most straight forward way is to find the cost per ounce.


detergent:
2.00 / 37 = .054...
2.37 / 38 = .062...
laundry detergent A is cheaper.


mustard:
.88 / 6 = .146...
1.61 / 12.5 = .1288...
mustard B is cheaper


canned tuna:
1.09/6 = .1816...
1.29/8.75 = .147...
canned tuna B is cheaper.


another way is to do a ratio analysis.


detergent:
if 37 ounces of detergent A costs 2.00, then 38 ounces of detergent A would cost 38/37 * 2.00 = 2.05...
since 38 ounces of detergent B cost 2.37, then detergent A is cheaper.

mustard:
if 6 ounces of mustard A cost .88, then 12.5 ounces of mustard A would cost 12.5/6 * .88 = 1.833...
since 12.5 ounces of mustard B cost 1.61, then mustard B is cheaper.


canned tuna:
if 6 ounces of canned tuna A cost 1.09, then 8.75 ounces of canned tuna A would cost 8.75 / 6 * 1.09 = 1.589...
since 8.75 ounces of canned tuna B cost 1.29, then canned tuna B is cheaper.


both methods will yield the same answer.