For this question, I am not very satisfied with the solution. I want to understand where am I going wrong because our 2 mutually exclusive categories are less than 6 hours of sleep and 6 or more hours of sleep. Previously, those who have answered have assumed two overlapping categories to be mutually exclusive.
According to me, the answer should be 34%. Here is my reasoning:
1. Let x be the total number of interns'
2. 80% of x are those who receive less than 6 hours of sleep, that means there are 20% of those interns who receive 6 or more than 6 hours of sleep. (These will be our two mutually exclusive categories)
3. Out of 80% x interns, there are 75% who report feeling of tiredness that means in this category of less than 6 hours interns there are 25% who don't report this feeling so the expression for this would be (0.25)(0.8)x
4. Now from the 20% interns who receive 6 or more than 6 hours of sleep there are 70% who don't report any feeling of tiredness so number of these students would be (0.7)(0.2)x
5. After solving we get these two expressions to add: 0.2x + 0.14x = 0.34x (There are 34% interns who report no feeling of tiredness irrespective of what sleeping hours they report
Why is this incorrect? Could someone please explain?