P, Q and R run at speeds of 4 m/s,5m/s and 6 m/s respectively around a circular track of length 50m. If they start from the same point and at the same time, after how many seconds would they meet for the first time?

This question awards 100 ! i really don’t want to fail i will also mark you !

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.

Solve for x where 0 equation: cot^2x+2cotx+1=0