Distance covered by Hallie before lunch= 1 5/8 km.
Converting it into imperoper fractions we get (1*8+5)/8= 13/8 km.
Distance covered by Hallie after lunch = 6 1/4 km.
Converting it into imperoper fractions we get (6*4+1)/4 = 25/4 km.
Difference between distances = Distance covered after lunch - Distance covered before lunch.
=25/4 km - 13/8 km
Subtracting fractions by taking common denominator, we get
25/4 - 13/8 = 50/8 - 13/8 = 37/8
Let us convert 37/8 into mixed fraction now.
On dividing 37 by 8, we get quotient 4, and 5 remainder.
So, 37/8 = 4 5/8.
Therefore, Hallie bikes 4 5/8 km farther after lunch than before lunch.