Answer:
Car B have to travel 10 miles on First Street to get to Oak Street
Step-by-step explanation:
Refer the attached figure.
First street = AB
Main Street = BC = 14 miles
Oak street = AC
We are also given that The intersection of Main Street and Oak Street forms a y° angle, and 
We will use trigonometric ratio

So, 

Hence Car B have to travel 10 miles on First Street to get to Oak Street