Multiple the cost of the water bottle ($2.75) then whatever you answer is, you subtract that from 18. She should have $12.5 left. The most bags of popcorn she could get is 3. Just add $3.50 until it’s closes to the amounts of money she has left.
so a percentage is really just like a fraction or decimal so were going to turn it into a decimal by moving the decimal point two places to the left making it .20 then to figure out the answer we're going to multiply 50 by .20 to get 10