Probability — practice question

On any given day, Kino goes to school by bus, by car or on foot with probabilities $0.2$, $0.1$ and $0.7$ respectively. The chance that he is late when he goes by bus is $x$. The chance that he is late when he goes by car is $2x$ and the chance that he is late when he goes on foot is $0.25$. The probability that Kino is late on a randomly selected day is $0.235$.