Mr. Bliss traveled 150 miles at a certain среднее rate. By increasing his rate 15 mph, he traveled 225 miles in the same time he spent on the 150 mile trip. Find his среднее rate on the trip.

Решение

M r . Bl i ss t r a v e l e d 150 mi l es a t a cer t ain a v er a g e r a t e . B y in cre a s in g hi s r a t e 15 m p h, h e t r a v e l e d 225 mi l es in t h e s am e t im e h e s p e n t o n t h e 150 mi l e t r i p . F in d hi s a v er a g e r a t e o n t h e t r i p .

trip 2 speed : 22.5

Шаги решения

Given Speed:

trip 1 : 15

Given Distance:

trip 1 : 150

trip 2 : 225

Represent the time in terms of

x :

trip 1 : t_{2}

trip 1 Speed 15 Time t_{2} Distance 150

Write an equation for trip 1Distance = Speed

\cdot

Time

150 = 15 x

Решите для

x, 150 = 15 \cdot x : x = 10

time : 10

Represent the speed in terms of

y :

trip 2 : y

trip 2 Speed y Time 10 Distance 225

Write an equation for trip 2Distance = Speed

\cdot

Time

225 = y \cdot 10

Решите для

y, 225 = y \cdot 10 : y = \frac{45}{2}

\frac{45}{2} = 22.5

trip 2 speed : 22.5