Steven left Town A & walked towards Town B at a speed of 100m/min. At the same time, Jason & Melvin started from Town B & walked ....towards Town A...

Steven walks from town A towards town B at 100m/min. Jason
walks from town B towards town A at 80m/min and Melvin walks from town B towards town A
at 75 m/min.

Let the distance between A and B be L. Let
Steven meet Jason after time T.

In time T Steven has
travelled a distance 100*T and Jason has walked a distance 80*T. As the two are coming
from opposite directions, they have covered the distance between the two
towns

=> 100T + 80T = L
...(1)

After 6 minutes Steven meets Melvin. Here Steven has
walked (T + 6)*100 and Melvin was walked (T + 6)*75.

Again
(T + 6)*100 + (T + 6)*75 = L

=> 100T + 600 + 75T +
450 = L

=> 175T + 1050 = L
...(2)

(1) and (2) give

180T =
175T + 1050

=> 5T =
1050

=> T =
1050/5

=> T =
210

Substitute in (2)

175T +
1050 = L

=> 175* 210 + 1050 =
L

=> 37800
m

The distance between the two towns is 37.8
km.