Question

PLEASE HELP IMMEDIATELY, I NEED A RESPONSE TONIGHT!!!

THANKS:) I'm giving all my points, 30.

Trains A and B, 200 km apart on the same straight track, travel at speeds of 50 km/hr and 65 km/hr respectively. At the end of 1 hour, the distance between the trains could not be
A. 85 km
B. 115 km
C. 185 km
D. 215 km


Apparently, the answer is B.) 115 km, but I need a solution.

Answer 1

Explanation:

The key fact is what are the trains doing: are they travelling toward one another or away from each other

Away from each other.

Train A has gone 50 km in 1 hour

Train B has gone 65 km in 1 hour.

They started off being 200 km apart

So their distance now is 50 + 65 + 200 = 315

Towards each other

This time they are eating into the 200 km

So you subtract

200 - 65 - 50 = 200 - 115 = 85 km.

Both trains are travelling in the same direct -- in B's direction

B - 65 + 50

200 - 15

185 km

Both trains are travelling in As direction

A - 50 + 65

200 + 15 = 215

The tricky part of this is which train is going in what direction?

As you can see, You have covered A C and D

The only one can't get is 115 (of course 315 didn't show up either).