Respuesta :

x+y = 4

x=4-y

52x+50y=204

52(4-y)+50y=204

208-52y+50y=204

208-2y=204

-2y=-4

y=2

x= 4-2=2


check 52*2=104

50*2 = 100

104+100=204

 so he traveled 2 hours at both 50 and 52 mph