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Beatrice participates in professional triathlons. She runs 2 mph faster than her friend Joe, a weekend athlete. If they each
run 12 mi, Beatrice finishes 30 min ahead of Joe. Determine how fast each person runs.

Answer :

nandhini123

Speed of  Joe is 6  mph and that of  Beatrice  is 8 mph

Step-by-step explanation:

Let Joe's speed be S

Beatrice's speed be s + 2

Let  Joe's time be  T

Beatrice's time = T - 1/2

Then

We know that

[tex]speed = \frac{distance}{time}[/tex]

Now

Distance  =[tex]speed \times time[/tex]

On substituting the value

Equation corresponding to Joe

[tex]12 = S \times T[/tex]...........................(1)

 Equation corresponding to Beatrice

[tex](S+2) \times (T - \frac{1}{2})=12[/tex]

Now solving for s and T,we get

[tex](S+2) \times (\frac{12}{S}- \frac{1}{2})=12[/tex]

[tex](S+2) \times (\frac{24 -S}{2S})=12[/tex]

[tex]2S(S+2) \times ({24 -S})=12(2S)[/tex]

[tex](2S^2 - 4S )(24-S) = 24S[/tex]

S = 6 mph -------------------------- Joe's speed

T = 2 hours ------------------------ Joe's time

Thus Beatrice's speed  is

6 + 2 = 8 mph

Beatrice's time is

[tex]2 -\frac{1}{2} =1\frac{1}{2 }hours[/tex]

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