Finding the speed

Question

Two trains leave Paris at the same time one traveling north and the other south ata speed that is 15 mph faster than the north bound train in 2 hours the trains are 230 miles apart find the speed of each train

Answer 1

The train travelling north has a speed of X mph

 

hence the south bound train has a speed of X + 15 mph

 

since they head in directly opposite direction their effective speed is the sum of each

 

hence the effective speed is X + X + 15 = 2X + 15

 

distance = speed * time

 

230 = (2X + 15)*2

 

115 = 2X + 15

 

100 = 2X

 

50 = X

 

Hence the northbound train has a speed of 50 mph and the southbound 65 mph