Anna enjoys dinner at a restaurant in Washington, D.C., where the sales tax on meals is 10%. She leaves a 15% tip on the prices of her meal before the sales tax is added, and the tax is calculated on the pre-tip amount. She spends a total of 27.50 for dinner. What is the cost of here dinner without tax or tip?<spanclass=′latex−bold′>(A)</span>$18<spanclass=′latex−bold′>(B)</span>$20<spanclass=′latex−bold′>(C)</span>$21<spanclass=′latex−bold′>(D)</span>$22<spanclass=′latex−bold′>(E)</span>$24