A travel agent offers a vacation plan which costs 'a' dollars for the first day, and a/10 for each additional day. How much does a vacation of b days cost, where b > 1. Choose the correct choice from the following choices:
A) (ab+9a)/5
B) (ab+8a)/10
C) (ab+9a)/2
D) (ab+5a)/10
E) (ab+9a)/10
Cost = a + (b-1)*a/10 = (10a + (b - 1)*a)/10 = (ab+9a)/10   Answer is (ab+9a)/10
<result>E</result>
A travel agent offers a vacation plan which costs 'a' dollars for the first day, and a/10 for each additional day. How much does a vacation of b days cost, where b > 1.