Abhimanyu, a businessman, lost his important documents at a crowded railway station. Ramesh, a passerby, voluntarily collected the documents and…

Abhimanyu, a businessman, lost his important documents at a crowded railway station. Ramesh, a passerby, voluntarily collected the documents and returned them safely to Abhimanyu without expecting any reward. A week later, impressed by Ramesh’s honesty, Abhimanyu wrote and signed a promise to pay him - 50,000 as a reward. Later, Abhimanyu refused to pay, arguing that the act had already been performed voluntarily and therefore did not constitute valid consideration. Ramesh filed a case claiming that the promise was binding. Decide, under the Indian Contract Act, 1872, whether Abhimanyu is liable to pay.