In a college, 300 graduates sit for the recruitment drive of three com...
Steps 1 & 2: Understand Question and Draw Inferences
We are given that 300 graduates from a college participate in recruitment process conducted by companies A, B, and C. The results of the process are as follows:
Let’s say:
X = the number of students who got placed in A
Y = the number of students who got placed in B
Z = the number of students who got placed in C
P = the number of students who got placed in B and C
Q = the number of students who got placed in A and C
R = the number of students who got placed in A and B
S = the number of students who got placed in all three companies
T = the number of students who were not placed in any of the companies
Now, per the question:
X + Y + Z + P + Q + R + S + T = 300 ………… (1)
X + P + Q + S = 80 …………. (2)
Y + P + S + R = 180 …………. (3)
Z + Q + S + R = 120 …………. (4)
S = 5 …………. (5)
We need to find the value of T. However, we have 8 variables and only 5 equations. So, we need three more equations in these variables to find the value of T.
Step 3: Analyze Statement 1
Statement 1 says: Out of the number of graduates who got placed in A, 75 and 45 are also placed in B and C respectively.
Per this statement,
The number of students placed in A and B = 75
We know from the diagram that the students placed in A and B consist of R and S. So,
R + S = 75
So, R = 70 ………….. (6)
Note that, since S represents the number of students who were placed in all the three companies, it includes the number of students who were placed in A and B.
The number of students placed in A and C = 45
We know from the diagram that the students placed in A and B consist of Q and S. So,
Q + S = 45
So, Q = 40 ………….. (7)
Thus, we get a total of 7 equations, but we have 8 variables. So, we still can’t find the value of T.
Hence, statement I alone is not sufficient to answer the question: What is the value of T?
Step 4: Analyze Statement 2
Statement 2 says: Out of the number of graduates who got placed in C, 35 are also placed in B.
The number of students placed in B and C = 35
We know from the diagram that the students placed in B and C consist of P and S. So,
P + S = 35
So, P = 30 ………….. (8)
Thus, we get a total of 6 equations (5 from Steps 1 and 2, and another one in this step, from Statement 2), but we have 8 variables. So, we still can’t find the value of T.
Hence, statement II alone is not sufficient to answer the question: What is the value of T?
Step 5: Analyze Both Statements Together (if needed)
Since statement I and II alone are not sufficient to answer the question, let’s analyse both the statements together:
Now, the combination of both the statements gives us 8 equations in 8 variables, we can easily find the value of T. By plugging in the values of P, Q, and R, we get:
Now, by plugging in the values of P, Q, R, and S in the following equations, we get:
X + Y + Z + P + Q + R + S + T = 300 ………… (1)
X + P + Q + S = 80 …………. (2)
Y + P + S + R = 180 …………. (3)
Z + Q + S + R = 120 …………. (4)
X = 5
Y = 75
Z = 5
Thus, from equation (1):
5 + 75 + 5 + 40 + 30 + 70 + 5 + T = 300
230 + T = 300
So, T = 70
So, there are total 70 students who were not placed in any of the companies.
Both statements together are sufficient to answer the question.
Answer: Option (C)
(Note: We have solved for the value of T only to illustrate how such an answer could be calculated if one wanted to solve for T. The given question is a Data Sufficiency question, and therefore, you as a student need not solve for the value of T. Once you determine in Step 5 that you have 8 equations and 8 variables, and therefore the two statements together are sufficiency to find a unique value of T, you can-you should! – stop there and confidently mark the answer as C)