word problem

Question

You are a purchasing agent, and from one source you always buy 1000 items, namely 10 widgets and 990 doodads. In the past widgets and doodads always cost $1 each, so you paid $1000. Now the price of widgets and the price of doodads have both increased by 10% to $1.10. By how much has the total you pay increased? What percentage of $1000 is that increase? (This number is the percentage increase in the total paid.) Is the answer found simply by adding 10% to 10% to get 20%?

Answer 1

old total payment = $1000. new total payment = 1000 * 1.10 = $1100 total has increased by $1100 - $1000 = $100. Percent increase = (100/1000) * 100% = 10%.