Find two rational numbers whose sum is -10,0,15

The table shows a pattern of exponents. what is the pattern as the exponents decrease?

Jordan rides his bike 6 7/15 miles every day to deliver newspapers and to go to and from school. if his ride to and from school is 4 3/10 miles, how many miles is the trip to deliver newspapers? 1 1/3 1 1/6 2 1/6 2 4/5

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items