Find the distance between A and B, if Jimmy travelled from A and B at 100 km/h. This trip would take him 3 hours more at 80km/h

Answer 1

It depends on how advanced your math is...
You could do this question merely by looking at the patterns
If you consider
a) 100km distance between them then at 100km/h it took 1 hr and at 80km/h it took under two hours so the time is NOT 3 hours more. So you must up the distance
b) 200 km distance... at 100km/h it took 2 hours at 80km per hour it took over two but under three hours... thus NOT 3 hours more.
c) 600 km distance... at 100km/h it took 6 hours while at 80km/h it took 0ver 7 hours but under 8, so still not enough time between them
d) the pattern continues and at this point you may see that you need to hike the distance up some
e) 1200 km ... at 100km/h it takes 12 hours while at 80 km/hour (1200/80=15 hours) thus it takes 3 hours more when they are driving their speeds and have to go 1200 km.

Answer 2

d = V * T = 100 * T = 80 * (T+3).
100T = 80*(T+3),
100T = 80T + 240,
T = 12h.

d = V*T = 100 * 12 = 1200 km.