Respuesta :
Answer:
(a) 10.5 miles/hour
(b) 6.5 miles
Step-by-step explanation:
(a)
Carla runs [tex]2\frac{5}{8}=\dfrac{21}{8}[/tex]
time taken by Carla=15 minutes=15/60 hours.
Hence Average rate of speed = total distance/total time
=[tex]\dfrac{21}{8}\times\dfrac{60}{15}\\\\=10.5[/tex]
Hence, the average rate of speed in miles per hour is 10.5 miles/hour.
(b)
on Tuesday Carla decides to jog instead of walk and decreases her speed by 20%(20/100=0.2).
so her speed=10.5-0.2×10.5
=8.4 miles/hour.
Now distance travelled by her in 50 minutes(50/60 hours)=8.4×(50/60) miles
=6.5 miles.
Answer:
(A)
[tex]v=\frac{7}{42240}mph[/tex]
(B)
[tex]d=\frac{7}{63360}miles[/tex]
Step-by-step explanation:
(A)
We are given
distance traveled is
[tex]=2\frac{5}{8}= \frac{8\times 2+5}{8}=\frac{21}{8}in[/tex]
we know that
1 inch = [tex]\frac{1}{12}feet[/tex]
We can multiply both sides by 21/8
[tex]\frac{21}{8}in=\frac{1}{12}\times \frac{21}{8} feet[/tex]
[tex]\frac{21}{8}in=\frac{7}{32}feet[/tex]
so,
[tex]d=\frac{7}{32}feet[/tex]
we know that
1 mile =5280 feet
[tex]d=\frac{7}{32}\times\frac{1}{5280} miles[/tex]
[tex]d=\frac{7}{168960}mile[/tex]
time is 15 minutes
we know that
160 min =1 hour
so,
[tex]15min=\frac{15}{60}hour[/tex]
[tex]15min=\frac{1}{4}hour[/tex]
[tex]t=\frac{1}{4}hour[/tex]
now, we can find speed
[tex]v=\frac{d}{t}[/tex]
now, we can plug values
[tex]v=\frac{\frac{7}{168960}}{\frac{1}{4}}[/tex]
now, we can simplify it
[tex]v=\frac{7}{42240}mph[/tex]
(B)
On Tuesday Carla decides to jog instead of run and so decreases her average rate of speed by 20 percent
so, average speed becomes
[tex]v=\frac{7}{42240}\times\frac{80}{100} mph[/tex]
[tex]v=\frac{7}{52800}mph[/tex]
We are given
time =50 min
now, we can find time in hour
[tex]t=\frac{50}{60}hr= \frac{5}{6}hr[/tex]
we know that
distance = (velocity)*(time)
we get
[tex]d=\frac{7}{52800}\times \frac{5}{6}miles[/tex]
[tex]d=\frac{7}{63360}miles[/tex]
