Answer :
A bicyclist rode a distance of 21 miles in 75 minutes. What was her speed in miles per hour?
Step 1
Let
1 hour =60 min
Step 2
using a rule of three, convert 75 minutes into hours
if
[tex]\begin{gathered} 60\text{ min}\Rightarrow1\text{ hour} \\ 75\text{ min }\Rightarrow\text{ x hour} \end{gathered}[/tex]the relaton is
[tex]\begin{gathered} \frac{60}{1}=\frac{75}{x} \\ \text{solve for x} \\ 60x=75 \\ x=\frac{75}{60} \\ x=1.25 \end{gathered}[/tex]then, 75 minutes = 1.25 hours
Step 3
find the speed
Let
distance=21 miles
time=1.25 hours
[tex]\begin{gathered} \text{speed}=\frac{dis\tan ce}{\text{time}}=\frac{21\text{ miles}}{1.25\text{ hours}} \\ \text{speed}=16.8\text{ miles per hour} \end{gathered}[/tex]so, the answer is 16.8 miles per hour
