ANSWER
20 miles
EXPLANATION
We have that Bob rides his bike to his firiend's house.
He rode 16 miles and that was 4/5 of the way.
Let the total distance from Bob's house to his friend's house be x.
This means that:
[tex]\begin{gathered} \frac{4}{5}\cdot\text{ x = 16} \\ \text{Solve for x:} \\ \frac{4x}{5}\text{ = 16} \\ \text{Cross multiply:} \\ 4x\text{ = 5 }\cdot\text{ 16 = 80} \\ x\text{ = }\frac{80}{4} \\ x\text{ = 20 miles} \end{gathered}[/tex]Bob's house is 20 miles from his friend's house.
