First you convert the fractions into improper fractions to make adding simpler by multiplying the denominator by the whole number and then adding that to the numerator.
3 3/4 = 15/4 and 2 1/8 = 17/8
Next, you change 15/4 into 30/8 so that you could add the fractions together. (The denominators have to be the same)
Then you just add the numerators: 30/8 + 17/8 = 47/8 = 5 7/8
Answer: 5 7/8 pounds in total