Gina is travelling to the beach 20 miles away from her house.
On Ginas map her house and the beach are 4 inches apart
That is a distance of 20 miles is represented by the Ginas map in 4 inches
Therefore, on Ginas map one inch will be = 20/4 miles = 5 miles
So, the scale used for Gina's map is 1 inch = 5 miles
Hope this helps..!!
Thank you :)