我想問一條maths題.

題目:
In a country, if we take a taxi, the fare is $5 for the first 2 km and $2 for every 1 km in the remaining journey. Mr Wong took a taxi from his home to an airport and the journey was x km in total.
(a)The distance between Mr Wong's home and the airport was more than 2 km. Express the required fare in terms of x.
(b)If Mr Wong paid a fare of $41, how long was the journey in total?
(c)If Mr Wong took a taxi at the airport and travelled 30 km to a train station, how much did he pay?

我要列式同答案.
THX=]