The answer is D because 6 3/4 in an improper fraction is 27/4. 5 1/2 in an improper fraction is 11/2. If you want to add 27/4 and 11/2, then you have to multiply both the numerator and denominator of 11/2. Now, 11/2 will be turned into 22/4. 27/4+22/4=49/4. Now, you have to turn 2 1/4 into an improper fraction to subtract. 2 1/4 will be turned into 9/4. 49/4 - 9/4=40/4. 40/4 is simplified to 10. So the answer is, D.
The answer is D. No, the answer is not reasonable. It should be about 10 pounds. I know because first I converted 5 1/2 into 5 2/4 (which is equivalent). Then I added 6 3/4 and 5 2/4 together to get 12 1/4. Then I subtracted 2 1/4 from 12 1/4 to get 10. Hope this helped! <span />