Susanna is buying lunch for her friends at a restaurant the bill is $50 and she wants to leave an 18% tip P equal the total amount of Suzanne is P which equation can you use to find P please help

Every weekday, mr. jones bikes from his home to his job. sometimes he rides along two roads, the long route that is shown by the solid lines. other times, he takes the shortcut shown by the dashed line. how many fewer kilometers does mr. jones bike when he takes the shortcut instead of the long route?