Anna and David left an 18% tip after having dinner at a restaurant. The amount of the tip was $9. Anna’s dinner cost $28. Which equation can you use to find x, the cost of David’s dinner?
Call the cost of David's dinner D.
9 = 0.18 • (D + 28) The tip equals 18% of the total of David's and Anna's dinners.
9 = 0.18D + (0.18 • 28)
0.18D = 9 – 5.04 I switched sides because I like the unknown on the left. It's a personal preference.
0.18D = 3.96
3.96
D = ——— = 22 David's dinner cost $22.00
0.18
.