question: Ashley's pizza delivery costs $15. What is the total amount that Ashley should give the delivery man if she wants to give a tip that is equal to 1/5 of the amount she ordered?
answer: The tip that Ashley wants to give amounts to $15 x 1/5 = $<<15*1/5=3>>3.
  Hence, she will give a total of $15 + $3 = $<<15+3=18>>18 to the delivery man.
  #### 18