Question

Consider the following exam question and student solution. Determine whether the solution is correct. If it is not​ correct, write a note to the student explaining why it is wrong and give a correct solution.

Exam​ question: You can buy a 32
​-pound
bag of flour for ​$9

or you can buy a​ 1-pound bag for  ​$0.45
.
Compare the per pound cost for the large and small bags.

Student​ solution: The large bag price is 32
divided by ​$9equals​$3.56
per​ pound, which is much more than the 45 cents

per pound price of the small bag.

Answer 1

Answer:

See explanation

Step-by-step explanation:

Large bag:

You can buy a 32​-pound bag of flour for ​$9, then 1 pound costs

$\ 9\div 32=\ 0.28125\approx \ 0.28$

Small bag:

You can buy a​ 1-pound bag for $0.45.

Compare:

$0.28<0.45,$

the large bag price is less than the small bag price.

Mistake:

Student apllied incorrect division: instead of dividing the price by the number of pounds, he divided the number of pounds by the price (this gives him the amount of pounds per one dollar)