A.
Multiply the number of days, x by 50 per day to get 50x.
Next multiply the number of miles driven to the amount she gets per mile: 0.60 x 200 = $120
Now add both together to equal the total of 1620.
The equation becomes: 50x +120 = 1620
B.
50x +120 = 1620
Step 1: subtract 120 from both sides ( subtraction property of equality):
50x = 1500
Step 2: Divide both sides by 50 ( division property of equality):
x = 1500 / 50
x = 30
C.
The trip lasted 30 days.