A northbound train left at noon Two hours later a southbound

A northbound train left at noon. Two hours later, a southbound train left the same station. At 6:00 p.m., the two trains were 490 miles apart. Find the rate of each train if the northbound train traveled 15 miles per hour faster than the southbound train.

Solution

490=(R-15)*6+R*4
490=6R-90+4R
490=10R-90
10R=490+90
10R=580
R=580/10
R=58 MPH FOR 4 HOURS FOR THE SOUTH BOUND TRAIN
THUS THE NORTH BOUND TRAIN WAS TRAVELING
58-15=43 MPH FOR 6 HOURS
PROOF
490=43*6+58*4
490=258+232
490=490