Posted by
**Jessica** on
.

Two cars leave town going in the same direction. One travels 55 mph and the other travels 65 mph How long will it take before they are 180 miles apart?

Hint: We do know that one car is 180 miles ahead of the other, so the slow car's distance can be represented by " d " and the distance of the fast car, which would be ahead, can be represented by "d + 180." The time is the same again, and can be represented by "t." This time we have two unknowns, so we need two equations, one for the fast car, and one for the slow car. Again we are using the basic formula d = rt , and substituting the values that are relevant to our situation. The equation for the slow car is: d = 55t. You write the equation for the fast car, and solve the system by substitution. Don't forget the units in your answer.

In the same direction.

distance slow= 55*time

distance fast= 65*time

But we know the distance between= distance fast - distance slow.

180= distancefast-distanceslow

or distancefast= 180 + distanceslow.

so substutute that in the second equation.

distancefast= 65*time

180+distanceslow= 65*time

but distance slow= 55*time then

180+55*time=65*time

solve for time

180= 65*time -55*time

180= (65 -55)time

time= 18 hrs

check that.

so then the answer is 18 hours?

or do you just want me to check that?