A worker may claim Rs.$$15$$ for each km which he travels by taxi and Rs.$$5$$ for each km when he drives his own car. If in a week he claimed Rs. $$500$$ for travelling $$80$$ km, how many km did he travel by taxi?
The correct option is A $$10$$
Let the worker traveled $$x$$ km by taxi.
Thus, $$15 \times x + (80 - x) \times 5 = 500$$
$$10x + 400 = 500$$
$$x = 10$$
Thus, he traveled $$10$$ km by taxi.