Probability

A person goes office either by car, scooter, bus or train, proability of which being \(\frac{1}{7}, \frac{3}{2}, \frac{2}{7}\) and \(\frac{1}{7}\), respectively. Probability that he reaches office late, if he takes car, scooter, bus or train is \(\frac{2}{9}, \frac{1}{9}, \frac{4}{9}\) and \(\frac{1}{9}\), respectively. Given that he reached office in time, then what is the probability that he travelled by a car?