<span>There are 100 * 99 = 9900 different ways to choose two students out of 100 bandmembers. You and our brother are 2 of that ways: you being selected first and you being selected second. Therefore the probability that you two are selected is 2 / 9900 = 0,000202. You can also think as the probability of you being selected among 100 bandmembers, which is 1/100, times the probability of your brother being selected among 99 members, which is 1/99 => (1/100) * (1/99) = 1/ (100*99) = 1 / 9900; plus the same for your brother being selected first and you second => [1/9900] * 2 = 2/9900, which is the same calculated above.</span>

6 0

3 years ago

1/2(6 2/3+1/4)-5/24=

Helen [10]

For this case we must simplify the following expression:

$\frac {1} {2} (6 \frac {2} {3} + \frac {1} {4}) - \frac {5} {24} =$

We convert the mixed number to an improper fraction:

$6 \frac {2} {3} = \frac {3 * 6 + 2} {3} = \frac {20} {3}$

So, by rewriting we have:

$\frac {1} {2} (\frac {20} {3} + \frac {1} {4}) - \frac {5} {24} =\\\frac {1} {2} (\frac {4 * 20 + 3 * 1} {4 * 3}) - \frac {5} {24} =\\\frac {1} {2} (\frac {80 + 3} {12}) - \frac {5} {24} =\\\frac {1} {2} (\frac {83} {12}) - \frac {5} {24} =$