This is a cross multiplication, proportion problem. 50 miles in 55 minutes is to x miles in 75 minutes.
50/55= x/75
Now we cross multiply
(50*75)=(55*x)
3750=55x
Divide both sides by 55 to isolate x
68.18=x
You can travel 68.18 miles in 75 minutes.
Hope this helps!! :)