Can someone plz help me with questions 2-4?

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

Solve for n? [tex]z = \frac{3}{4} mn[/tex]

Awoman has 14 different shirts: 10 white shirts and 4 red shirts. if she randomly chooses 2 shirts to take with her on vacation, then what is the probability that she will choose two white shirts? show your answer in fraction and percent, round to the nearest whole percent.