Answer:
200 miles
Explaination:
in order to fiind the point of interaction you must put the world problem into an liner equation.
y=mx+b
key:
miles : x
y= 0.70x + 120
&
y= 0.90x + 80
now you put them together
0.70x + 120 = 0.90x + 80
-0.70x. -0.70x
____________________ subtract slope from both sides
120 = 0.20x + 80. ( doesn't matter which one)
-80 - 80
____________________ subtract
40 = 0.20x
_________ Divide each # with the slope
0.20 0.20
200 = x
hope this helps!