Question

The distance d, that a certain car is from math city after h hours, can be determined by the equation d =45h. The distance that a second car is from math city can be determined by the equation d= 25h+80. after how many hours will the two cars be the same distance from the math city

Answer 1

This problem is about equations.

The first car have the next equation for your distance from math city:

$d=45h$

where d is the distance and h is our unknown value.

And for the second car the equation for distance is:

$d=25h+80$

So, we want to know the value of h which make d equal value for both cars. That's mean:

$45h=25h+80$

Now, we isolate h from the equation above:

$\begin{gathered} 45h=25h+80 \\ 45h-25h=80 \\ (45-25)h=80 \\ 20h=80 \\ h=4 \end{gathered}$

The answer is h=4 hours.