Starting at home, Jessica traveled uphill to the toy store for 12 minutes at just 10 mph. She then traveled back home along the same path downhill at a speed of 30 mph. What is her average speed for the entire trip from home to the toy store and back?

Respuesta :

Answer: 15 mph


Step-by-step explanation:

Given: Time taken to travel uphill to the toy store= 12 minutes[tex]=\frac{12}{60}=0.2\ hour[/tex]

Let d be the distance(in miles) between the home and toy store.

Also, [tex]Speed=\frac{Distance}{Time}[/tex]

[tex]\\\Rightarrow10=\frac{d}{0.2}\\\Rightarrow\ d=0.2\times10=2[/tex]

Thus, distance from home to toy store= 2 miles

When she turn back, to home distance remains same.

The time taken by her to come back at 30 mph speed=

[tex]Time=\frac{Distance}{speed}=\frac{2}{30}=\ hour[/tex]

Now, the average speed =[tex]\frac{\text{Total distance}}{\text{Total time}}[/tex]

[tex]=\frac{2+2}{0.2+\frac{2}{30}}\\=\frac{4}{\frac{6+2}{30}}\\=\frac{4\times30}{8}=\frac{120}{8}=15\ mph[/tex]

Answer:

the answer is 15

Completed by Jerome Maples Jr.

Step-by-step explanation: