Claudia is on a motorcycle trip. she checked the odometer at the beginning of the trip, and it showed 16,789 miles. after 15 days it showed 22,189 miles. if claudia rode the same number of miles each day, how many miles did she ride in a day?

First, subtract the final number displayed in the odometer from the initial value. 
                                     d = 22189 miles - 16789 miles = 5400 miles
Divide this value by the number of days Claudia had a motorcycle trip.
                                          rate = 5400 miles / 15 days
The number of miles that she ride per day is 360 miles. 

To get the answer to this question, you would start by subtracting the miles.
22,189 - 16,789 = 5,400
Then you would divide that by the number of days. 
5,400 / 15 = 360. 
Claudia rode 360 miles each day, assuming that she rode the same number each day. 

No a triangle cannot be formed because when you add the two smallest number together (which would be 11) the have to be bigger than the number it is "against" ( which would be 12)