[Question]: Hannah's AdBlock blocks all but 20% of ads, and 20% of the ads it doesn't block are actually interesting. What percentage of ads aren't interested and don't get blocked?
[Answer]: First find the percentage of ads that aren't interesting: 100% - 20% = 80%. Then multiply that percentage by the percentage of ads that don't get blocked to find the percentage of ads that meet both criteria: 80% * 20% = 16%.
So the answer is 16.

[Question]: Duke was at a garage sale when he spotted DVDs on sale. They were separated by price into 2 different boxes. In the first box, he found 10 movies that he wanted. These were $2.00 apiece. The second box was marked $5 each and he found 5 movies he wanted. What was the average price of each of the DVDs he bought?
[Answer]: In the first box he bought 10 DVDs at $2.00 each, so he paid 10 * 2 = $20.00. In the second box he bought 5 DVDs at $5.00 each, so he paid 5 * 5 = $25.00. He bought 10 + 5 = 15 DVDs. He spent $20 + $25 = $45.00. The average price of each DVD is $45 / 15 = $3.00 each.
So the answer is 3.

[Question]: A charity is delivering chicken and rice dinners to a shelter for the hungry. They have a hundred plates to deliver. The rice cost ten cents a plate and the chicken cost forty cents a plate. How many dollars did the charity spend on the food for the dinners?
[Answer]:
Each chicken and rice plate cost 10 + 40 = 50 cents. The charity spent 50 * 100 = 5000 cents for the dinners. There are 100 cents in a dollar, so the charity spent 5000 / 100 = $50 for the dinners.
So the answer is 50.