Let the speed of the train going from Boston to New York = X
Let the distance from Boston to when the trains meet = Y
The distance to New York when they meet would be 220 - Y
The Boston to New York train would be: Y = (2X-10)*2
New York to Boston train would be : 220 -Y = 2X
Using substitution:
220-(2X-10)*2 = 2X
Simplify the left side:
220 - 4X+20 = 2X
Add 4x to both sides and combine like terms:
240 = 6X
Divide both sides by 6:
x = 40
Now find distance from Boston by replacing x with 40"
Y = (2(40)-10)*2
Y = 160 -20
Y = 140 miles
