Question

3. Jeremy asked a sample of 40 8th grade students whether or not they had a curfew. He then asked if they had a set bedtime for school nights. He recorded his data in this two-way frequency table. Bedtime 21 Curfew No Curfew Total No Bedtime Total 4 25 12 16 40 3 15 24 a. What percentage of students surveyed have a bed time but no curfew?

Answer 1

40 students (the total) represents 100%

To find what percentage represents 3 students (number of students with bedtime but no curfew), we can use the next proportion:

`\frac{40\text{ students}}{3\text{ students}}=\frac{100\text{ \%}}{x\text{ \%}}`

Solving for x,

`\begin{gathered} 40\cdot x=100\cdot3 \\ x=(300)/(40) \\ x=7.5\text{ \%} \end{gathered}`