Mark took a total of 18 quizzes over the course of 2 weeks. How many weeks of school will Mark have to attend this quarter before he will have taken a total of 81 quizzes? Assume the relationship is directly proportional.

Aroulette wheel has 38 slots in which the ball can land. two of the slots are green, 18 are red, and 18 are black. the ball is equally likely to land in any slot. the roulette wheel is going to be spun twice, and the outcomes of the two spins are independent.the probability that it lands one time on red and another time on black in any order is(a) 0.5 (b) 0.25 (c) 0.4488 (d) 0.2244