Two Buses: How Long to Catch Up?

[Jimbo57]

Homework Statement

Two buses are moving at constant speeds, in the same direction, the first at 42km/h and the second at 54km/h. They are 18km apart. How long will it take the second bus to catch up to the first?

Homework Equations

The Attempt at a Solution

Seems pretty easy, but I've been out of high school for a while so my confidence is relatively low. Here's my attempt:

42t = 54t - 18
18 = 54t - 42t
18 = 12t
t = 1.5 hours

 

[phinds]

yep

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