A math problem, average speed, need help?

Vaughn drove from his house to work at a average speed of 25 mph and returned home from work on the same route at an average speed of 35 mph. If the entire trip took 2 hours, how many minutes did it take Vaughn from his house to work?





the choices are


a. 25


b. 30


c. 60


d. 70


e. 80





i really need to spoon fed this answer so i can use it as template for other like problems thank you so much

A math problem, average speed, need help?
House to work time = T


Work to house time = 2 - T





D = RT {distance = rate x time}





Since the distance is the same





25T = 35(2 - T)


25T = 70 - 35T


60T = 70


T = 70/60 = 1 1/6 = 1 hr 10 min
Reply:Answer is 70 minutes.


In these problems you are going to have to write two simultaneous algebraic equations for the two variables involved and solve.





r=d/t and u=d/(2-t) where r is the average speed from house to work and u is the average speed from work to house. t is the time it takes to go from house to work. d is the distance from house to work which is the same as the distance from work to house.


Substituting the values in:


25=d/t 35=d/35(2-t)


25t=d 70-35t=d


Solving the two equations; 25t=70-35t


60t=70


t=70/60


t=7/6 hour=70 minutes
Reply:distance = speed x time





The distances are equal, and the total trip took 2 hours. Therefore, it took x hours to work, and 2 - x hours back.





25x = 35(2 - x)


25x = 70 - 35x


60x = 70


x = 1.17 hours or 70 minutes

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