SOLUTION: Libby drive to work 1 hour. If she increases her average speed by 10 miles per hour, the trip takes 3/4 hour. Find the distance she drives to work

Let x be Libby's regular speed (in the first scenario), in miles per hour.


Then the distance to work is  distance = d = time*speed = 1 hour * x miles per hour = x miles.


This distance is equal to time*speed in the second scenario:


d = 0.75*(x+10)  miles.    (0.75 of an hour = 3/4 of an hour.)


Distance is the same, which gives you an equation


x = 0.75*(x+10),


Simplify and solve for x:


x = 0.75x + 7.5,

x - 0.75x = 7.5

0.25x = 7.5  ====>  x =  = 30 miles per hour.


Answer.  The distance to work is 30 miles.

Let distance be D

Then we get the following SPEED equation: 



3D + 30 = 4D

30 = 4D - 3D

Distance, or 

IGNORE all other INCORRECT ANSWERS.