Management Aptitude Test Sep 2013 Paper

(d)Let the probability that C wins = x
Then, probability that B wins = 2x
and probability that A wins = 4x
Then, sum of all probability for an event to happen is equal to 1
x + 2x + 4x = 1
7x = 1 ⇒ x = $\frac{1}{7}$
∴ Probability that C wins = 1/7
Similarly, probability that A wins = 4/7
Now, the probability that A loses = 1 - $\frac{4}{7}=\frac{3}{7}$