Uncle Bradley has a $1000 bill that he wants to change into smaller bills so he could give them to his nieces and nephews. He wants to change 3/10 of the money into $50 bills while the rest into $100 bills. How many pieces of bills will Uncle Bradley have in all? Let's think first. Chain of thought:
There will be $1000 x 3 / 10 = $300 worth of money that will be changed into $50 bills. Uncle Bradley will have $300 / $50 = 6 pieces of $50 bills. He will change $1000 - $300 = $700 worth of money into $100 bills. So there will be $700 / $100 = 7 pieces of $100 bills. Thus, there will be a total of 6 + 7 = 13 pieces of $50 and $100 bills in all.
Therefore, the answer is 13.