At a jog a thon you get 1$ at the starting line, 3$ for lap one, 9$ for lap 2 what is the equation

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

Three friends went on a road trip from phoenix, az, to san diego, ca. mark drove 50 percent of the distance. jason drove 1/8 of the distance. andy drove the remainder of the distance. 1. andy thinks he drove 1/4 of the distance from phoenix, az, to san diego, ca. is andy correct? 2. the distance from phoenix, az, to san diego, ca, is 360 miles. how many miles did each person drive? 3. solve the problem. what is the answer in total?

New york is the 27th largest state in the united states. what percent of the 50 states in the us are larger than new york