Question 1175414
<i>a. In how many ways can this be done if it does not matter how many of those chosen are joggers and how many are nonjoggers?</i>
<pr>
25C5 = {{{25!/(5!*20!)}}} = <b>53130</b>
<pr>
<i>b. In how many ways can this be done if exactly 3 joggers must be chosen?</i>
<pr>
10C3 * 15C2 = {{{(10!/(3!*7!)) * (15!/(2!*13!))}}} = 120 * 105 = <b>12600</b>
<pr>
<i>c. Find the probability that exactly 3 of the 5 people randomly selected from the group are joggers.</i>
<pr>
{{{(10C3 * 15C2)/(25C5)}}} = {{{((10!/(3!*7!)) * (15!/(2!*13!)))/(25!/(5!*20!))}}} = {{{(120 * 105)/53130}}} = {{{12600/53130}}} = {{{60/253}}} = <b>0.2372</b>