+0

# HELP with math homework

0
138
3

5) Natalie was running a race with her friend. Natalie’s friend ran 23 miles of the race. Natalie ran 12 mph slower than her friend. If Natalie’s friend ran the race in 3 hours, and 12 minutes, how fast did Natalie run the race?

Guest Mar 4, 2017
Sort:

#1
+76870
0

3hr, 12minutes  =   3.2 hrs

And   Distance  / Time  = Rate....so

23miles / 3.2hours     =  7.1875 mph  =  rate of Natalie's friend

Thus....it's impossible that Natalie ran 12mph slower than this  !!!!!

CPhill  Mar 5, 2017
#2
0

I think when you say "12mph slower", I believe you mean "12 miles slower than her friend over the same distance of 23 miles"??!!. If so, then it means that when her friend finished the 23-mile run, Natalie was still 12 miles from the finish line. Therefore, Natalie's speed was:[23 - 12] / 3.2 hours =3.4375 mph. Then,the time it takes Natalie to finish the race would be:

23 / 3.4375 =6.69 hours, or about 6 hours and 41.4 minutes.

Guest Mar 5, 2017
#3
+7059
0

Natalie was running a race with her friend. Natalie’s friend ran 23 miles of the race. Natalie ran 1.2 mph slower than her friend. If Natalie’s friend ran the race in 3 hours, and 12 minutes, how fast did Natalie run the race?

$$v_F=\frac{23miles}{3\frac{12}{60}h}=7.1875\ miles/h$$

$$v_N=7.1875\ mph-1.2\ mph=5.9875\ mph$$

$$t_N=\frac{s}{v_N}=\frac{23miles}{5.9857mph}=3h\ 50min\ 28.81sec$$

$$Natalie \ run \ the \ race \ in \ 3h\ 50min\ 28.81sec.$$

!

asinus  Mar 5, 2017
edited by asinus  Mar 5, 2017

### 8 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details