Question

A bus travels 0.8 mile east every 45 seconds. A second bus travels 0.55 mile west every 30 seconds. The buses start at the same location. Use two methods to determine how far apart the buses are after 15 minutes.

Answer 1

32.5 miles

Explanation:

Given that:

Eastbound bus :

0.8 miles every 45 seconds

Speed per second :

0.8 / 45 = 0.0177777 miles per second

Distance after 15 minutes

(15 * 60) * 0.0177777 = 16 miles

Westbound bus:

0.55 miles every 30 seconds

Speed per second :

0.55 / 30 = 0.0183333 miles per second

Distance after 15 minutes :

(15 * 60) * 0.0183333 = 16.5 miles

Distance apart :

16 miles + 16.5 miles = 32.5 miles

METHOD 2:

Distance covered after 15 minutes :

15 minutes = 15 * 60 = 900 seconds

Distance apart after 900 seconds :

[0.8 * (900/45)] + [0.55 * (900/30)]

16 + 16.5

= 32.5 miles