Question: A park has 50 benches with a capacity of 4 people each. On a Sunday afternoon, 80 people were sitting on the benches. What's the number of available spaces on the benches that other people can sit on before the carrying capacity of the benches is full?
Answer: In the park, 50 benches with a capacity of four people each have a total capacity of 50 * 4 = 200 sitting spaces. If 80 people are already using spaces, the number of empty spaces is 200 - 80 = 120. The answer is 120.

Question: Chris has twelve marbles, and Ryan has twenty-eight marbles. If they put marbles together in a pile and then each takes away 1/4 of marbles from the pile, calculate the number of marbles remaining in the pile.
Answer: If Chris and Ryan put together their marbles in a pile, the pile will have 12 + 28 = 40 marbles. If they then take 1 / 4 of the marbles each, every person will receive 1 / 4 * 40 = 10 marbles. Both of them will have taken a total of 10 + 10 = 20 marbles. The number of marbles remaining in the pile is 40 - 20 = 20. The answer is 20.

Question: Oliver had $9, then he saved $5 from his allowance and spent $4 on a frisbee and $3 on a puzzle. His friend gives him another $8 as it's his birthday. How much money does Oliver have left?
Answer: The total amount of money saved is $9 + $5 = $14. The total cost of the frisbee and the puzzle is $4 + $3 = $7. So Oliver has $14 - $7 = $7 left. His friend gives him $8, so now he has $7 + $8 = $15. The answer is 15.

Question: A cake of 400 grams is divided into eight equal parts. Nathalie eats one-eighth of the cake, and Pierre eats double what Nathalie ate. How much did Pierre eat, in grams?
Answer:
Nathalie ate 1 / 8 * 400g = 50g of cake. Pierre eats 2 * 50g = 100g of cake. The answer is 100.