Math question - PROBABILITY?

Question

The Mustangs basketball team wins 85% of its games.

1. Find the probability that the Mustangs will win exactly 3 of their next games.

2. Find the probability that the Mustangs will win at least 3 of their next 4 games.

Best answer goes to whoever gives me the correct answer and explains exactly HOW they got that answer. THANKS!

Answer 1

1. I'm assuming that a word was left out ("exactly three of their next FOUR games").
3 wins in 4 games =

a) probability of win, cubed, times
b) probability of loss, times
c) number of combinations of one loss and 3 wins

= (0.85)^3 * (1 - 0.85) * 4
= 0.368475

2. AT LEAST three wins, is the sum of three wins (above) and four wins. Four wins is:

= (0.85)^4 * (1 - 0.85)^0 * 1
= 0.52200625

That, plus the probabiltiy of three wins (above) is:

= 0.368475 + 0.52200625
= 0.89048125

So it's 89% (roughly) that they win three or four out of four.

Answer 2

1. (.85*.85*.85) = .61

2. P(win at least 3) = P(win exactly 3)+P(win exactly 4) = (4*.85*.85*.85*.15) +(.85*.85*.85*.85) = .89

The 4 is needed in the (4*.85*.85*.85*.15) because there are 4 choices for the game that is not won.

Answer 3

Shouldn't you be doing your own homework?