Question

One freshman, 2 sophomores, 4 juniors, and 5 seniors receive top scores in a school essay contest. To choose which 2 students will read their essays at the town fair; 2 names are chosen from a hat. What is the probability that a junior and then a senior are chosen?

Answer 1

5/33 oe 0.1515

Explanation:

Total = 1 + 2 + 4 + 5 = 12

4/12 × 5/11 = 5/33

= 0.1515151515

Answer 2

5/33

Explanation:

The total number of names in the hat is 1+2+4+5 = 12

P(junior) = # juniors/ total = 4/12 = 1/3

Then we remove the name so there are 11 names in the hat

One freshman, 2 sophomores, 3 juniors, and 5 seniors

P(2nd name is senior) = # seniors/ total = 5/11

P( junior,then senior no replacement) = 1/3 * 5/11

= 5/33