Answer:
Hmm.. not quite sure why you multiplied A with 10 yds. I am going to assume M=meters.
A.) You can convert to whatever units you like, but I am going to convert into meters.
0.89/yd * 0.9144yd/m = $0.97 > $0.94.. So.. A Lumber yard is selling the same rope for less expensive.
B.) You convert feet until you get to the correct units. like this....
550 ft * 1yd/3ft * .9144m/yd * $.97/m = $162.62
550 ft * 1yd/3ft * .9144m/yd * $.94/m = $157.58
taking the difference would be $5.03.
I believe for answer A, you forgot to convert...or converted differently. Hope this helps.
Explanation: