# An airplane travels 300 mi/h south for 2.0 hour and then at 250 mi/h north of 750 miles. What is the average speed for the trip?

Jun 14, 2017

$270$ mi/hr

#### Explanation:

Average speed = total distance / total time taken.

To south,
Velocity, ${v}_{1} = 300$, time, ${t}_{1} = 2$hrs

Distance, ${D}_{1} = {v}_{1} \cdot {t}_{1} = 300 \cdot 2 = 600$ miles

To north,
Velocity, ${v}_{2} = 250$, distance, $D 2 = 750$ miles

Time, ${t}_{2} = {D}_{2} / {V}_{2} = \frac{750}{250} = 3$ hrs

Average speed $= \frac{{D}_{1} + {D}_{2}}{{t}_{1} + {t}_{2}}$.

$= \frac{600 + 750}{2 + 3} = \frac{1350}{5} = 270$ mi/hr