Question

summarize the number of left-handed students and right-handed students by gender for the eighth grade students at Keisel Middle School. There are 5 times as many right-handed female students as there are left-handed female students, and there are 9 times as many right-handed male students as there are left-handed male students. if there is a total of 18 left-handed students and 122 right-handed students in the school, which of the following is closest to the probability that a right-handed student selected at random is female? (Note: Assume that none of the eighth-grade students are both right-handed and left-handed.)

Answer 1

50 / 122

Explanation:

let

female left handed students = x

female right handed students = 5x

male left handed students = y

male right handed students = 9y

according to the question,

x + y = 18 (1)

9y + 5x = 122 (2)

from eq. (1)

x = 18 - y

substituting the value of x in eq. (2)

9y + 5(18 - y) = 122

9y + 90 - 5y = 122

4y = 32

thus, y = 8

x = 10

the probability of selecting a female right handed student at random is:

50 / 122