Answer:
-88 mph
Step-by-step explanation:
We can use the relation ...
time = distance/speed
to compare the times in the two directions.

The wind speed is -88 miles per hour.
_____
The problem statement tells us the travel is slower <em>with</em> the wind than <em>against</em> the wind. Hence "with the wind" must be subtracting from the net speed. That is, the wind speed is negative.
(cube root of 5) * sqrt(5)
--------------------------------- = ?
(cube root of 5^5)
This becomes easier if we switch to fractional exponents:
5^(1/3) * 5^(1/2) 5^(1/3 + 1/2) 5^(5/6)
------------------------ = --------------------- = ------------- = 5^[5/6 - 5/3]
[ 5^5 ]^(1/3) 5^(5/3) 5^(5/3)
Note that 5/6 - 5/3 = 5/6 - 10/6 = -5/6.
1
Thus, 5^[5/6 - 5/3] = 5^(-5/6) = --------------
5^(5/6)
That's the correct answer. But if you want to remove the fractional exponent from the denominator, do this:
1 5^(1/6) 5^(1/6)
---------- * ------------- = -------------- (ANSWER)
5^(5/6) 5^(1/6) 5