math
posted by Martin .
your family is driving to houston,texas.A sign indicates that you are 700 miles from houston.Your car's trip odometer indicates you are 400 miles from home.YOu are traveling at an average speed of 60 miles per hour.
A. write an expression for the distance(in miles) you will be from houston in x hours
B. Write an expression for the distance (in miles) you will be from home in x hours.
C. use the expressions from parts (a) and (b) to write and solve an equation to find the number of hours you will drive until you are exactly halfway between houston and your home.
D. suppose you travel by local roads instead of the highway.you travel the 700 miles at a speed of 45 miles per hour.How long will you drive before you are exactly halfway between houston and your home?
im sorry i don't understand this
please help me thank you.

A. You need practice turning word problems into equations. This is not as hard as it looks. Consider A.
When you are 400 miles from home, you are 300 miles from Houston (assuming you are going in the right direction). In x hours, you will be 60 x miles closer to Houston. Subract that from 300 miles and you have the remaining distance to Houston.
B. At time zero you were 400 miles from home. At time t you are 60 t miles farther away. How do you get the total miles from home? Think about it.
Make an effort on these and let us know if you want further help. 
um im sorry i still don't understand
this 
8 yrs later are you done with this problem