Bunuel
During the break of a football match, the coach will make 3 substitutions. If the team consists of 11 players among which there are 2 forwards, what is the probability that none of the forwards will be substituted?
A. \(\frac{21}{55}\)
B. \(\frac{18}{44}\)
C. \(\frac{28}{55}\)
D. \(\frac{28}{44}\)
E. \(\frac{36}{55}\)
Probability approach.
First selection. The probability that no one of the forwards be selected from pool of 11 players means that will be selected any from other 9 players = 9/11.
Second selection. The probability that no one of the forwards be selected from pool of 10 remained players means that will be selected any from other remained 8 players = 8/10.
Third selection. The probability that no one of the forwards be selected from pool of 9 remained players means that will be selected any from other remained 7 players = 7/9.
Sought probability means that all three probabilities, that we've already found, appeared at the same time = 9/11 * 8/10 * 7/9 = 28/55