Question 1187999

By car, John travels from a city A to city be in three hours. At a rate that was 20 mph greater than Jones, Peter traveled the same distance than two hours. Find the distance between the two cities.
<pre>Let D be the distance between the cities
Then John's and Peter's speeds are: {{{matrix(1,3, D/3, and, D/2)}}}, respectively
We then get the following SPEED equation: {{{matrix(1,3, D/3, "=", D/2 - 20)}}}
2D = 3D - 120 ----- Multiplying by LCD. 6 
2D - 3D = - 120
Distance between the cities, or {{{highlight_green(matrix(1,6, D, "=", (- 120)/(- 1), "=", 120, miles))}}}