Question

A small airplane flies 1200 miles with an average speed of 300 miles per hour. 2 hours after the plane leaves, a Boeing 747 leaves from the same point. Both planes arrive at the same time.what was the average speed of the boeing 747?

Answer 1

The small plane has the following parameters

Distance = 1200 miles

Speed = 300miles/hour

time = ?

$\begin{gathered} \text{Speed =}\frac{dis\tan ce}{time} \\ time\text{= }\frac{1200}{300} \\ \text{time = 4 hours} \end{gathered}$

If a Boeing 747 leaves 2 hours later, the total time becomes 4hours + 2 hours = 6 hours

Considering the distance of the small plane after 6 hours, we have

$\begin{gathered} \text{distance = sp}eed\times\text{ time} \\ d\text{ = 300 }\times6 \\ d\text{ =1800 miles} \end{gathered}$

So the total distance = 1800 miles

Hence the speed of the Boeing 747 will be

$\begin{gathered} \text{Speed =}\frac{dis\tan ce}{time} \\ \text{distance = 1800 miles } \\ time\text{ = 2hours} \end{gathered}$$\begin{gathered} \text{speed = }\frac{1800}{2} \\ \text{speed = 900 miles/hour} \end{gathered}$

The average speed of the Boeing 747 is 900 miles/ hour