Answer :
Hello!
Let's write this as an equation below.
310/3+d=295/d
As you can see, we can cross-multiply this proportion giving us the equation below.
310d=295(3+d)
310d= 295d+885
Now, we subtract 295d from both sides.
15d=885
Now we divide both sides of the equation by 15.
d=59
Therefore, Dana travels 59 mph.
I hope this helps!