Many of the immigrants settled on farm land and they had to drive to town for supplies. One farmer drives to town at 36 miles per hour and returns at 48 miles per hour. If his total driving time is 3 ½ hours, how far is his farm from town?
the time taken each way is the distance divided by the speed. Total time = 3.5 hours
d/36 + d/48 = 7/2
multiply through by 288 = 6*6*8
8d + 6d = 7/2 * 6 * 6 * 8 = 1008
14d = 1008
d = 72
Check:
72/36 = 2
72/48 = 1.5