Question

Your brother and sister took turns driving on a 580 mile trip that took 10 hours to complete. your brother drove at a constant speed of 55 miles per hour and your sister drove at a constant speed of 60 miles per hour. how long did each person drive.

Answer 1

let the time the boy drove be x and that the girl drove be y:
x+y=10
thus
x=10-y........i

distance=speed*time
the distance each one drove will be:
55x+60y=580....ii
substituting i in ii we get:
55(10-y)+60y=580
550-55y+60y=580
5y=30
y=6 hours
thus
x=10-6=4 hours
hence the boy drove for 4 hours and the girl for 4 hours