set up a proportion:
[tex] \frac{3000}{75} [/tex]=[tex] \frac{4000}{x} [/tex]
To solve cross multiply:
3000x=300000
divide both sides by 3000:
3000x/3000=300000/3000
x=100
It will take her 100 hours to drive 4000 miles assuming she continues to travel at this rate.
