Calorimetry, Latent Heat & Mechanical Equivalent of Heat question from NEET 1999 (AIPMT)

Answer: (c)

1. Ice needs $80 + 100 = 180\text{ cal}$ to become water at $100^{\circ}\text{C}$.
2. Steam gives $540\text{ cal}$ just by condensing at $100^{\circ}\text{C}$, which is more than $180\text{ cal}$.
3. So only part of the steam condenses and the mixture stays at $100^{\circ}\text{C}$.
4. So the answer is (c) $100^{\circ}\text{C}$.