Polly has a certain number of dollar bills in her purse and no change. she spends half the
money on a scarf and gives $1 to a homeless person outside the store. she spends half the
remaining dollars for lunch and tips the waiter $2. she then spends half of what she has
left for a cd, and just before she goes home she spends $3 on a smoothie. she has $1
left. how many dollars did she begin with?