SAT Mathematics Practice Test 4

Since the price of Ken’s sandwich was $\mathit{x}$ dollars, andPaul’s sandwich was 1 dollars more, the price of Paul’s sandwich was x + 1 dollars.Thus, the total cost of the sandwiches was $2\mathit{x}+1$ dollars. Since this cost was split evenly, Ken and Paul each paid $\frac{2\mathit{x}+1}{2}=\mathit{x}+0.5$ dollars plus a 20% tip. After adding the 20% tip, each of them paid dollars.
Choices A, B, and D are incorrect. These expressions do not model the given context. They may be the result of errors in setting up the expression or of calculation errors.