Chapter 4.8, Problem 1P

To determine

To calculate: the time of the jet & plane passing each other.

Answer to Problem 1P

They passed at noon 2:20 P.M.

Explanation of Solution

Given:

	$\text{speed}\times \text{time = Distance}$
Plane	$?$	t	$?$
Jet	$?$	$?$	$?$

Speed of the plane left from Austin to los Angeles= 500kmph

Speed of the jet left fromlos Angeles to Austin = 700 kmph

Distance betweenAustin to los Angeles = 2100 kmph

Calculation:

Let the time taken by the plane = $x$

Let the time taken by the jet= $x-1$

Speed of the plane = 500 kmph

Speed of the jet = 700 kmph

Distance covered by plane = $500\times x$

Distance covered by jet = $700\left(x-1\right)$

Now total distance

  $\begin{array}{l}500x+700\left(x-1\right)=2100\\ 500x+700x-700=2100\\ 500x+700x=2100+700\\ 1200x=2800\\ x=\frac{2800}{1200}\\ x=\frac{7}{3}\text{hrs}\end{array}$

2 hrs 20 minutes

	$\text{speed}\times \text{time = Distance}$
Plane	$500$	$\frac{7}{3}$	$1166.67$
Jet	$700$	$\frac{4}{3}$	$933.33$