37.
Add all the distances .
3/4 + 1/2 + 2/3 + 3/4 = 8/3 miles
To add fractions you need equal bottom numbers
find the LCM ( Least common multiple of the denominators )
4 , 2 , 3 , 4 = LCM = 12
Multiply each fraction by the same numerator and denominator, to obtain 12 as a bottom number
(3/4 * 3/3) + (1/2 * 6/6) + (2/3 * 4/4) + (3/4 * 3/3)
9/12 + 6/12 + 8/12 + 9/12
Now that all fractions have the same denominator ( bottom number) you can add them.
Add the numerators ( top numbers ) and put 12 as a denominator.
(9 + 6 + 8 + 9 ) / 12 = 32/12
Simplify ( divide both numbers by 4 )
32/12 = 8/3