A travel agent offers a vacation plan which costs x dollars for the first day, and x/3 for each additional day. How much does a vacation of y days cost, where y > 1.
Choose one.
A) (yx-3x)/3  B) (yx+4x)/2  C) (yx+5x)  D) (yx+2x)/3  E) (yx-x)/3
Cost = x + (y-1)*x/3 = (3x + (y - 1)*x)/3 = (yx+2x)/3   Answer is (yx+2x)/3
<result>D</result>
A travel agent offers a vacation plan which costs x dollars for the first day, and x/3 for each additional day. How much does a vacation of y days cost, where y > 1.