Question 1027166
A battalion 20 miles long advances 20 miles. During this time, a messenger on a horse travels from the rear of the battalion to the front and immediately turns around, ending up precisely at the rear of the battalion upon the completion of the 20-mile journey. How far has the messenger traveled?
<pre>Let the number of miles the battalion traveled, when the messenger got to its front, be M
Then number of miles the battalion traveled, when the messenger traveled from the front to the rear = 20 - M

The messenger traveled the length of the battalion, or 20 miles, plus the distance the battalion had traveled when he/she got to the front

He/She then traveled the length of the battalion (20 miles), once again, plus the distance the battalion had traveled when he/she got to the rear 

So, the messenger traveled a total of: 20 + M + 20 + 20 - M, or {{{highlight_green(matrix(1,2, 60, miles))}}}