MAH-CET 2026 — Reasoning PYQ

Step 1: Parse the Premises

1. Premise 1: "All bats are mammals."

   • This means the set of "Bats" ($B$) is completely contained inside the set of "Mammals" ($M$).

   • Mathematical notation: $B\subseteq M$

2. Premise 2: "Some mammals fly."

   • This means there is an intersection between the set of "Mammals" ($M$) and the set of things that "Fly" ($F$).

   • Mathematical notation: $M\cap F\ne \varnothing$

Step 2: Evaluate the Conclusion

The question gives a tentative deduction: "Therefore, some bats fly." Let's test if this conclusion definitely follows from the premises using standard logic:

• The set of flying things ($F$) intersects with mammals ($M$).

• However, this intersection could completely avoid the subset of bats ($B$). It is entirely possible that the mammals that fly are completely distinct from bats (e.g., flying squirrels or hypothetical mammals).

• Because a certain link between $B$ and $F$ cannot be established definitively, the conclusion "some bats fly" is a fallacy (specifically, the fallacy of the undistributed middle). It is not logically certain.

Step 3: Evaluate the Multiple Choice Options

Since the prompt asks to select the correct valid alternative based on standard syllogistic patterns, let's see which statement is a 100% true immediate inference:

• (a) All bats can fly: Invalid. Cannot be deduced from the premises.

• (b) Some bats fly: Invalid. As proven above, this is a logical fallacy based strictly on the premises.

• (c) Some mammals are bats: Valid. Since "All bats are mammals" ($B\subseteq M$), it naturally and unconditionally implies its converse conversion: "Some mammals are bats" ($M\cap B\ne \varnothing$). If the entire circle of bats sits inside mammals, that overlapping region guarantees some mammals are indeed bats.

• (d) No bats fly: Invalid. While it is possible, it is not definitely guaranteed by the premises either.

Correct Answer

The correct option is (c) Some mammals are bats.