A person goes to the office either by a car, or scooter, or bus, the probability of which being $\frac{2}{7},\frac{3}{7},\frac{2}{7}$ respectively. The probability that he reaches office late if he takes a car, or scooter, or bus is $\frac{2}{9},\frac{1}{9},\frac{4}{9}$ respectively. If he reaches office in time, the probability that he travelled by car is $k$, then the value of $24k+7$ is equal to