请教一道Prep的题 请NN们帮忙看看那

1. A certain taxi company charges $3.10 for the first  of a mile plus $0.40 for each additional   of a mile.  What would this company charge for a taxi ride that was 8 miles long?

(A) $15.60

(B) $16.00

(C) $17.50

(D) $18.70

(E) $19.10

答案D

我很讨厌taxi计费的题那 请教各位那 小女子在此谢谢啦