Question 1195806: In a year 10 maths class, there are 30 students. Each student is either 15 or 16 years old, and either left or right-handed.
The ratio of right-handed students to left-handed students is 4:1, the ratio of 15-year-olds to 16-year-olds is 1:2 and the ratio of left-handed 15-year-olds to left-handed 16-year-olds is 1:5.
If the names of the students in this class are placed in a hat and one is selected at random, what is the probability that the student selected is 15 years old and right-handed?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! 10 students are 15 and 20 students are 16
24 students are RH and 6 are LH. Of the 6 who are LH, 5 are 16 and 1 is 15
16 year-olds number 20, and 5 are LH and 15 RH
15 year-olds are 10, 1 is LH and 9 RH.
Therefore, there are 9 RH 15 year-olds out of the 30 students, so the answer is 0.30.
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