Calculating Time for Car to Catch Up to Truck

[Wanting to Learn]

Homework Statement

A car traveling 93 km/h is 250 m behind a truck traveling 81 km/h.
How long will it take the car to reach the truck (in seconds)?

Homework Equations

d=tv

The Attempt at a Solution

d_c = 93t
d_t = 81t
d_c = d_t + 250
93t = 81t + 250
12t = 250
t = 250/12
t = 20.83h = 75,000sec

The online homework website (I just started AP Physics 1) says that is the incorrect answer. Where did I go wrong? Do I need to use a different equation(s)?

Thank you in advance for helping.

 

[Wanting to Learn]

Oh I just realized maybe I need to change the km to m or vice versa... will try that and then post whether it works.

 

[Wanting to Learn]

Okay, having converted 250m to 0.25km and redoing the calculation I got the correct answer.