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 questions: You can buy a 44- pound bag of flour for $7 or you can buy a 1- pound bag for $0.39. Compare the per pound cost for the large and small bags. Student solution: The large bag price is 44 ÷ $7 = $6.29 per pound, which is much more than the 39 cedis per pound price of the small bag. Select the correct choice below and if necessary, fill in the answer box to complete your choice.

A. The students solution is correct
B. The students solution is incorrect. The students division gives an answer with units of pounds per dollar, but he should seek an answer in dollars per pound. The answer in dollars per pound is $..... per pound, which is less than the $0.39 per pound of the smaller bag. ( round to the nearest cent as needed)
C. The students solution is incorrect. The student should have converted 39 cedis per pound to dollars per pound before writing the exam solution. He should have converted 39 cedis cents pe r pound to $ .... per pound.( Round to the nearest cent as needed)

Answer 1

The student calculated the price per pound of the large bag of flour incorrectly by inverting the division operation. The correct cost per pound for the large bag is $0.159, which is cheaper than the small bag price of $0.39 per pound.

Step-by-step explanation:

The student's solution is incorrect. The correct way to compute the price per pound of the large bag is to divide the total price of the bag by its weight in pounds. Therefore, to calculate the cost per pound for the 44-pound bag of flour priced at $7, you divide $7 by 44 pounds. This calculation yields the correct cost per pound for the large bag of flour.

The correct calculation is as follows: $7 ÷ 44 pounds = $0.159 per pound (rounded to the nearest cent). This value is significantly less than the $0.39 per pound cost of the smaller 1-pound bag of flour. Hence, the correct option is B, implying that the large bag of flour offers a better price per pound compared to the small bag.

The student solution is incorrect. To compare the per pound cost for the large and small bags, we need to calculate the cost per pound for each bag. The student correctly divided the cost of the large bag by its weight, but their answer is in pounds per dollar instead of dollars per pound.

To get the correct answer, we need to invert their answer. The cost per pound for the large bag is $7 ÷ 44 = $0.1591. So, the per pound cost for the large bag is $0.16, which is less than the per pound cost of the small bag ($0.39).