Question 626682
d = r * t  (Distance is rate times time).<P>
Call the lorry's speed L and the car's speed C.<P>
The distance they travel is the same, so 4L = 2.75C<P>
The distance the car must make up in some time (t) is the time of head start the lorry had, times the lorry's speed, which is:  .75L and that equals the car's speed times the time (t) so .75L = Ct<P>
Use the first equation to find L in terms of C.  4L=2.75C so L = 2.75/4 * C = .6875C.<P>
Substitute that into the second equation:
.75(.6875C) = Ct so .515625C = Ct and .515625 = t = approx 30.9 minutes.

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