Answer:
250 miles
Step-by-step explanation:
Let number of mile driven be x
plan 1: Cost = 0.7x
plan 2: Cost = 50 + 0.5x
for both plans to cost the same,
Plan 1 Cost = Plan 2 Cost
0.7x = 50 + 0.5x (solve for x)
0.7x - 0.5x = 50
0.2x = 50
x = 250 miles