Question: Derek was 6 years old when he had three times as many dogs as cars. Ten years later, after selling some of his dogs and buying 210 more cars, the number of cars became twice the number of dogs. How many dogs does Derek have now if he had 90 dogs when he was six years old?
Answer with step-by-step thinking: At six years old, with three times as many dogs as cars, Derek had 90 / 3 = 30 cars. Ten years later, after buying 210 more cars, Derek has 210 + 30 = 240 cars. Since the number of cars is twice as many as the number of dogs, Derek currently has 240 / 2 = 120 dogs.
So the answer is 120.

Question: Francine wants to know if a local chemical plant is releasing toxic waste that makes the frogs mutate. In one local pond, she catches 5 frogs with extra legs, 2 frogs with 2 heads, two frogs that are bright red, and 18 normal frogs. What percentage of the frogs have mutated, rounded to the nearest integer?
Answer with step-by-step thinking: First add up the numbers of the three kinds of mutant frog: 5 frogs + 2 frogs + 2 frogs = 9 frogs. Then add that number to the number of normal frogs to find the total number of frogs: 9 frogs + 18 frogs = 27 frogs. Finally, divide the number of mutant frogs by the total number of frogs and multiply by 100% to find the percentage of frogs that are mutants: 9 frogs / 27 frogs * 100% = 33.333...%, which rounds to 33%.
So the answer is 33.

Question: A small poultry farm has 300 chickens, 200 turkeys and 80 guinea fowls. A strange, incurable disease hit the farm and every day the farmer lost 20 chickens, 8 turkeys and 5 guinea fowls. After a week, how many birds will be left in the poultry?
Answer with step-by-step thinking:
There are 300 + 200 + 80 = 580 birds in total. Every day 20 + 8 + 5 = 33 birds are lost. After a week which is 7 days, 33 * 7 = 231 birds would be lost. There would be 580 - 231 = 349 birds left in the poultry.
So the answer is 349.