Question

roulette wheel spins with 38 slots: 18 red,18 black, and 2 green. A ball is spun and lands in a slot. Each slot has an equal chance of capturing the ball. roulette wheel spins 3 consecutive times and a ball lands each time on a red slot. What is the probability that the ball will land on a red slot on the next spin?

Answer 1

And odds against the ball landing in green slot are 36/38 or 18/19. It can also be found as 1-odds of ball landing in green slot i.e. $1–2/38=>(38–2)/38=>36/38$

The outcomes of one trial are independent of other trial

$P(red)=\frac{18}{38}\\ P(black)=\frac{18}{38}\\ P(green)=\frac{2}{38}\\ \implies \frac{(\frac{18}{38})^4}{(\frac{18}{38})^3}\\ P= 0.47$