Riyad can complete an assignment in 2 hours while omar can do the same assignment in 3 hours .they work together for an hour ,after which riyad left and omar had to finish the rest of the work alone. how much time in minutes will omar will require to finish the rest of the work?

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