In a special triathlon, Betty swam 2 miles in 25 minutes, biked 20 miles in 45 minutes, and then ran 5 miles in 40 minutes. how long in hours did Betty race?

Divide. reduce the answer to lowest terms.5 2/3 ÷ 3 1/9

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.

Simplify (8x2 − 1 + 2x3) − (7x3 − 3x2 + 1). −5x3 + 11x2 − 2 5x3 − 11x2 + 2 x3 + 2x2 + x3 x3 − 2x2 − x3