Please solve the three questions.

Thank you.

h. Why logistics network design tools use approximated rather than accurate transportation distance? How is the transportation distance approximated for metropolitan area and the continental U.S., respectively? i What are the differences between the buy-back contract and the quantity flexibility contract? } What are the drawbacks shared by both the buy-back and the revenue sharing contracts? h. Why logistics network design tools use approximated rather than accurate transportation distance? How is the transportation distance approximated for metropolitan area and the continental U.S., respectively? i What are the differences between the buy-back contract and the quantity flexibility contract? } What are the drawbacks shared by both the buy-back and the revenue sharing contracts