Question

A jet plane traveling at 450 mph overtakes a propeller plane traveling at 250 mph that had a 3​-hour head start. How far from the starting point are the​ planes?

Answer 1

It's suppose to add 450mph+250mph=700 then divide 3 hours=233.3

Answer 2

Answer:

1687.5 miles

Step-by-step explanation:

Given: A jet plane traveling at 450 mph overtakes a propeller plane traveling at 250 mph that had a 3​-hour head start.

To Find: How far from the starting point are the​ planes

Solution:

Speed of jet plane = $450$ $\text{mph}$

speed of Propeller plane = $250$ $\text{mph}$

Distance travelled by propeller plane in 3 hours head start = $\text{speed of propeller plane}\times\text{time}$

                                              = $250\times3$ = $750$ $\text{miles}$

Distance to be travelled by jet plane to overtake propeller plane =  $\text{distance between both planes}$

                                                       $750$  $\text{miles}$

Relative speed of both planes = $\text{Speed of jet plane}-\text{speed of propeller plane}$

                                                    $450-250=200$ $\text{mph}$

Time taken by jet plane to overtake propeller plane =  

                                         $\frac{\text{Distance between both planes}}{\text{relative speeds of planes}}$

                                                    $\frac{750}{200}=\frac{15}{4}$ $\text{hours}$

total distance travelled by plane = $\text{Time taken by jet plane to overtake propeller plane}\times\text{speed of jet plane }$

                                                       $450\times\frac{15}{4}=1687.5$ $\text{miles}$

planes are $1687.5$ $\text{miles}$ far from starting point.