Answer:A is the correct answer
Explanation:
Let x represent the number of female students that are left handed. There are 5 times as many right handed female students as there are left handed female students. This means that the number of female students that are right handed is 5x
Let y represent the number of male students that are left handed. There are 9 times as many right handed male students as there are left handed male students. This means that the number of male students that are right handed is 9x
The total number of left handed students is 18. Therefore
x + y = 18
The total number of right handed students is 122. Therefore
5x + 9y = 122 - - - - - - - - - -1
Substituting x = 18 - y into equation 1, it becomes
5(18 - y) + 9y = 122
90 - 5y + 9y = 122
- 5y + 9y = 122 - 90
4y = 32
y = 32/4 = 8
x = 18 - y = 18 - 8
x = 10
Total number of right handed female students is 5×10 = 50
Total number of right handed students is 122.
Probability that a right handed student selected at random is a female will be
50/122 = 0.4098
approximately 0.410