Abag has five red marbles, six blue marbles, and four black marbles. what is the probability of picking a blue marble, replacing it, and then picking a red marble

Naomi’s parents want to have 50,000, saved for her college education, if they invest 20000 today and earn 7% interest compound annually, about how long will it take them to save 50 thousand

What is the lcm of 16 and 40 ? 24 and 40 ?

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.