Answer:To find the number of students who want to be both a doctor and a social worker, we can use the Principle of Inclusion-Exclusion (PIE). This principle states that the total number of elements in the union of two sets is equal to the sum of the number of elements in each set minus the number of elements in their intersection.
So, the number of students who want to be both a doctor and a social worker can be calculated as:
|Doctor ∩ Social worker| = |Doctor| + |Social worker| - |Doctor U Social worker|
|Doctor ∩ Social worker| = 40 + 20 - 65
|Doctor ∩ Social worker| = -5
However, this result is negative which is not possible, therefore, no students want to be both a doctor and a social worker.
To find the number of students who want to be both, we have to find the number of students who want to be both a doctor and a social worker which is 0 in this case.
Explanation: