One car travels 40 km/hr faster than another. while one travels 150 km, the other goes 350 km. find the speed of the slower car.

So the speeds are s and s+40

distance=speed times time

if we assume the time is the same, and it is t

350=(s+40)(t)
and
150=(s)(t)
so

350=st+40t
150=st
multiply 2nd equation by -1 and add to first

350=st+40t
-150=-st +
200=+0st=40t

200=40t
divide both sides by 40
5=t
so
speed=disatnce/time
s=150/5
s=30

slower car is 30mph

In all honesty, there really is no “work” per say to show. mainly it’s just using the process of elimination. the question is asking which domain(s) would be the most appropriate for the function c(n). n is the number of observed vehicles so right away, 1, 2, and 3 can be eliminated.why? 1, 2 start in the negatives and therefore it is impossible to observe negative cars. so, #4 would be the best answer to the given problem.