Question: A farmer is selling ducks and chickens at the market. He sells ducks for $10 and chickens for $8. He sells 5 chickens and some ducks. He then spends half his earnings on a new wheelbarrow. After buying it, someone sees it and agrees to pay the farmer double what the farmer paid and the farmer earns another $60. How many ducks did the farmer sell?
Answer: The wheelbarrow cost $30 because 60 / 2 = 30. The farmer earned $60 from selling fowl because 30 / (1 / 2) = 60. The farmer earned $40 selling chickens because 5 x 8 = 40. The farmer earned $20 selling ducks because 60 - 40 = 20. The farmer sold 2 ducks because 20 / 10 = 2. The answer is 2.

Question: Daria wants to go to a concert by her favorite band. She wants to buy tickets for her and for three of her friends. One ticket cost is $90. How much money does Daria need to earn if she currently has only $189?
Answer: Daria wants to buy tickets for four persons, so the cost will be 4 tickets * $90 / ticket = $360. Daria currently has $189, so she needs $360 - $189 = $171 more. The answer is 171.

Question: Jack, who weighs 60 pounds, wants to play on the see-saw with his cousin Anna, who weighs 40 pounds. How many 4-pound rocks does Jack need to hold to make their weights equal?
Answer: First find the total difference in weight between the two people: 60 pounds - 40 pounds = 20 pounds. Then divide the weight difference by the weight of each rock to find the number of rocks need to even the weights: 20 pounds / 4 pound / rock = 5 rocks. The answer is 5.

Question: In a Zoo, there are different animals. There are 5 giraffes and twice as many penguins. Penguins make up 20% of all the animals in the Zoo. How many elephants are there in the Zoo if they make up 4% of all the animals?
Answer:
There are twice as many penguins as giraffes, so there are 5 * 2 = 10 penguins. The penguins make up 20% of all animals, so there are 100 / 20 * 10 = 50 animals in the whole Zoo. 4% of animals are elephants, so there are 4 / 100 * 50 = 2 elephants at the Zoo. The answer is 2.