Introduction to probability, please check my answers.

1.In how many diff. ways can a committee of 5 be selected from 62 members of a clinical staff.

5/62 *100 = 8.06%

2.In how many ways can a director of a research lab choose 2 chemists among 7 other applicants and 3 physicist from the applicants.

Chemist:2/7*100=28.57%

Physicist:3/7*100=42.86%

3.What is the possibility of drawing an ace from a well shuffled deck of 52 playing cards.

4/52*100=7.7%

4.If 3 of 20 tires are defective and 4 of them are randomly chose for inspection, what is the probability that 1 of the defective tires will be included.

3/20=.15 4/.15=26.67.

Any help will be appreciated, thank you