Answer:
Part a) The runner is travelling at [tex]20\ \frac{ft}{sec}[/tex]
Part b) The runner's speed is [tex]13.6\ \frac{mi}{h}[/tex]
Step-by-step explanation:
The complete question in the attached figure
Part a) we know that
The speed is equal to divide the distance by the time
Let
s ----> the speed
x ----> the distance
y ---> the time
[tex]s=\frac{x}{y}[/tex]
we have
[tex]x=100\ yd\\y=15\ sec[/tex]
Remember that
[tex]1\ yd=3\ ft[/tex]
Convert yards to feet
[tex]x=100\ yd=100(3)=300\ ft[/tex]
Find the speed
[tex]s=\frac{300}{15}[/tex]
[tex]s=20\ \frac{ft}{sec}[/tex]
Part b) we know that
[tex]1\ mi=5,280\ ft[/tex]
[tex]1\ h=3,600\ sec[/tex]
we have
[tex]x=300\ ft[/tex]
[tex]y=15\ sec[/tex]
Convert feet to miles
[tex]x=300\ ft=300/5,280\ mi[/tex]
Convert seconds to hours
[tex]y=15\ sec=15/3,600\ h[/tex]
substitute
[tex]s=\frac{x}{y}[/tex]
[tex]s=\frac{(300/5,280)}{(15/3,600)}[/tex]
[tex]s=\frac{300*3,600}{5,280*15}=\frac{1,080,000}{79,200}=13.6\ \frac{mi}{h}[/tex]
