61 = 3b + 7
3b + 7 = 61
3b = 61 - 7
3b = 54
b = 54/3
b = 18.
Answer:
4 miles
Step-by-step explanation:
In order to find how many miles the car will travel in 0.5 hours, we can set up a proportion.

We can now cross multiply to find the value of x.

So the car can travel 4 miles in 0.5 hours.
Hope this helped!