Question

If it is not correct, write a note to the student explaining why it is wrong and give a correct solution.Exam Question: A candy store sells chocolate for $7.70 per pound. The piece you want to buy weighs 0.11 pound. How much will it cost, to the nearest cent? (Neglect sales tax.)Student Solution: 0.11 ÷ 7.70 = 0.014. 0.11 ÷ 7.70 = 0.014. It will cost $0.014.

Answer 1

In order to find the cost of the piece of chocolate, we can use a rule of three.

The cost of one pound of chocolate is $7.70, so the cost of 0.11 pound of chocolate would be x:

`\begin{gathered} 1\text{ pound}\to7.7 \\ 0.11\text{ pound}\to x \\ \\ (1)/(0.11)=(7.7)/(x) \\ x=7.7\cdot0.11 \\ x=0.847 \end{gathered}`

Rounding to the nearest hundredth, the cost will be $0.85.

So the student solution is not correct. The student should multiply 0.11 by 7.70, and not divide them.