100 students appeared for two tests-Physics and Chemistry. 60 students...
Step 1: Question statement and Inferences
We are given that a total of 100 students appeared in the two tests. Out of these 100 students, 60 passed in Physics and 33 passed in Chemistry. The point to note here is that the question statement doesn’t say “60 students passed ONLY in Physics” or “33 students passed ONLY in Chemistry”. Therefore, the numbers given here are for the total number of students who passed in Physics and Chemistry respectively.
If a student passes in at least one test, the school gives him a cash prize of $1,000. We have to find the difference in the maximum and minimum possible values of the prize money that the school disbursed to the students.
Let’s say,
P = the number of students who passed only in Physics
C = the number of students who passed only in Chemistry
X = the number of students who passed both the tests
Given that,
Number of students who passed in Physics = 60
This means, P + X = 60
Or, P = 60 – X
Similarly, C + X = 33
This means, C = 33 – X
Let the number of students who qualify for money disbursement be Z.
Thus
Z = P + C + X
That is, Z = (60 -X) + (33 – X) + X
Z = 93 -X
As we can see, the value of Z depends on the value of X.
Case 1: Maximum value of Z
Z will be maximum when the value of X is the least. The lowest possible value of X is zero (X cannot be negative because it denotes the number of students)
Thus, Zmax = 93
Case 2: Minimum value of Z
Z will be minimum when the value of X is the maximum.
Since there are only 33 students who passed in Chemistry, X cannot exceed 33. Thus, the maximum value of X can be 33.
(Logically speaking: the number of students who passed BOTH Physics and Chemistry cannot be greater than the total number of students who passed Chemistry)
Thus, Zmin = 93 – 33 = 60
Step 2: Finding required values
Maximum possible amount of disbursement by the school = 1000* Zmax = 1000*93 = $93,000
Minimum possible amount of disbursement by the school = 1000* Zmin = 1000*60 = $60,000
Step 3: Calculating the final answer
The difference in the maximum and the minimum possible amounts of disbursement
= $93,000 -$60,000
= $33,000
Answer: Option (B)