Chapter 1 - Problem Solving and Critical Thinking - Chapter Summary, Review, and Test - Review Exercises - Page 45: 33

8 pounds

There are $7$ frankfurters in one pound. We need to supply $28$ people with $2$ frankfurters each. We need a total of $28*2=56$ frankfurters. We need a total of $56\div7=8$ pounds. Checking the solution: $(8*7)\div2=56\div2=28$