Question: John buys 500 newspapers. Each newspaper sells for $2. He sells 80% of them. He buys them all for 75% less than the price at which he sells them. How much profit does he make?
Answer: He sells 500 * .8 = 400 newspapers. He sells them for 400 * 2 = $800. He gets a discount of 2 * .75 = $1.5 on the newspapers. So he buys them for 2 - 1.5 = $.5. So he spent 500 * .5 = $250 buying them. That means he made a profit of 800 - 250 = $550. The answer is 550.

Question: Sam is serving spaghetti and meatballs for dinner. The pasta costs $1.00 per box, a jar of sauce is $2.00 and 1 pound of meatballs is $5.00. He wants to stretch this meal into 8 servings. How much does each serving cost?
Answer: The pasta is $1.00, the sauce is $2.00 and the meat is $5.00 for a total of 1 + 2 + 5 = $8.00. He wants to stretch this meal into 8 servings so each serving will cost 8 / 8 = $1.00. The answer is 1.

Question: James decides to replace his car. He sold his $20,000 car for 80% of its value and then was able to haggle to buy a $30,000 sticker price car for 90% of its value. How much was he out of pocket?
Answer: He sold his car for 20000 * .8 = $16,000. He bought the new car for 30,000 * .9 = $27,000. That means he was out of pocket 27,000 - 16,000 = $11,000. The answer is 11000.

Question: In the city, there is a block of flats. This block has 12 floors. Half of the floors have 6 apartments and the other half have 5 apartments. One apartment can accommodate a maximum of 4 residents. What is the maximum number of residents that can live in this block of flats?
Answer:
Half of the floors have different numbers of apartments. Half the number of floors is 12 floors / 2 = 6 floors. One half of the block consists of 6 floors * 6 apartments / floor = 36 apartments. And the other half consists of 6 floors * 5 apartments / floor = 30 apartments. There are 30 + 36 = 66 apartments on all floors in the block. All the apartments can therefore accommodate 66 apartments * 4 residents / apartment = 264 residents. The answer is 264.