Answer: they need to cover 0.25 miles.
Step-by-step explanation:
Let x represent the total distance that they have to cover to get to Bernie's house.
Beth and Billy are biking to their friend Bernie's house and after 1 mile, Beth and Billy have traveled 4/5 of the total distance to Bernie's house. This would be expressed as
4.5 × x = 1
4x/5 = 1
Multiplying the left hand side and the right hand side of the equation by 5, it becomes
4x/5 × 5 = 1 × 5
4x = 5
Dividing the left hand side and the right hand side of the equation by 4, it becomes
4x/4 = 5/4
x = 1.25
Therefore, the remaining distance that they need to cover to arrive at Bernie's is
1.25 - 1 = 0.25 miles
