Can someone ascertain which is the correct answer? two people gave two different answer. I am lost. Carcass

x+y-B+N=100

B is 9 and N is 0

x+y=75%

But you have no info about the split between x and y

D is the answer

I don’t think quantity A asks for only 1 of the hackathon but only 1 of both hackathons.

Per above solutions

It is asking for X + Y, not just X or Y. The answer should be A.

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Only one hackathon means only \(x\) or \(y\)

You're right i am getting the same answer even gemini pro is getting the same answer idk what these guys are saying.
It clearly says each student attents one of the two that means neither =0
75% attend one of the two that means x+y = .75T
we can find the total x+y this way.
and for the case that some people are saying that we don't know how to split x and y, that's the thing we don't have to.

I believe A is correct.

Let $T$ be the total number of students in the Computer Science club. Let $O$ be the number of students who attended only one hackathon. Let $B$ be the number of students who attended both hackathons.

Since all students went to at least one hackathon:

$$
\(T=O+B\)
$$

2. Use the Given Percentages and Counts
- We are given that 9 students went to both hackathons:

$$
\(B=9\)
$$

- We are given that $\(\mathbf{7 5}\)$ percent of the students went only to one hackathon:

$$
\(O=0.75 \times T\)
$$

3. Find the Percentage of Students who went to Both Hackathons
- If $75 %$ of the total students ( $T$ ) went to only one hackathon ( $O$ ), then the remaining percentage must be the students who went to both hackathons $(B)$.
- Percentage of students in $B=100 %-75 %=25 %$
4. Find the Total Number of Students ( $T$ )
- We know that $25 \%$ of the total students is equal to 9 students.

$$
\(\begin{gathered}
0.25 \times T=9 \\
T=\frac{9}{0.25}
\end{gathered}\)
$$

5. Calculate Quantity A

Quantity A is the number of students who attended only one hackathon $(O)$.
- Using the percentage:

$$
\(\begin{gathered}
O=75 \% \times T \\
O=0.75 \times 36 \\
O=27
\end{gathered}\)
$$

- (Alternatively, using the total minus those who went to both: $\(O=T-B=36-9=27\)$ )

\(27>18\)

A is the answer