Algebra quick question

Question

Two planes leave san Francisco one flying north and the other flying south the southbound travels 46 miles faster than the northbound plane after 4 hours they are 680 miles apart find the speed of each plane

Answer 1

680/4= 170 mph combined

x+46+x = 170

2x = 124

x = 62 mph for one plane

x+46 = 108 mph for 2nd plane

in 4 hours 1st goes 4(62) = 248 miles

while 2nd goes 4(108) = 432 miles

248+432 = 680