SOLUTION: There are 4 freshman, 6 sophomores, 7 juniors, and 3 seniors on a school field trip. Three students are needed to carry water bottle cases. How many different ways can these studen
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-> SOLUTION: There are 4 freshman, 6 sophomores, 7 juniors, and 3 seniors on a school field trip. Three students are needed to carry water bottle cases. How many different ways can these studen
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Question 1116312: There are 4 freshman, 6 sophomores, 7 juniors, and 3 seniors on a school field trip. Three students are needed to carry water bottle cases. How many different ways can these students be selected if they must be all three freshman or all three juniors? Answer by ikleyn(52776) (Show Source):
The number of way to select 3 students from 4 + 6 + 7 + 3 = 20 students is = 1140.
Of them, the number of favorable combinations is + = 4 + 35 = 39.
Therefore, the probability under the question is this number = 0.034 = 3.4%.
Solved.
In order to solve freely such problems, you need to know about Combinations.
