A man loves to go hiking. He knows that he has to pack about .5 pounds of supplies for every mile he hikes. He plans to go for a very long hike. He knows that he can get 1 resupply during the hike that will be 25% as large as his first pack. He can hike at a rate of 2.5 mph. He is going to hike 8 hours a day for 5 days. How much does he need to bring with his first pack? Give the rationale and then the answer.
Let's think step by step. He is going to hike 8 * = 40 hours. That means he will be hiking for 40 * 2.5 = 100 miles. So he needs 100 * .5 = 50 pounds of supplies. With the resupply he can get up to 1 + .25 = 1.25 times his initial pack. That means his initial pack has to weigh 50 / 1.25 = 40 pounds.. The answer is: 40.

A city has a population of 300,000. 50,000 people immigrate to the country and then 30,000 people leave. After that 1/8 of the population gets pregnant and 1/4 of those people have twins. How many people are there after the births? Give the rationale and then the answer.
Let's think step by step. There was a net immigration to the country of 50,000 - 30,000 = 20,000. So the total number of people before birth is 300,000 + 20,000 = 320,000. That means 320,000 / 8 = 40,000 get pregnant. So 40,000 / 4 = 10,000 have twins. So that means they have 10,000 * 2 = 20,000 children. There are 40,000 - 10,000 = 30,000 children from single births. So the total number of people is 320,000 + 30,000 + 20,000 = 370,000.. The answer is: 370000.

Carson is covering the high school football field with grass seed. Each square meter needs three times as much seed as fertilizer. If Carson uses 60 gallons of seed and fertilizer combined, how many gallons of seed does he use? Give the rationale and then the answer.
Let's think step by step. Let s be the number of gallons of seed Carson uses and f be the number of gallons of fertilizer. We know that s = 3f and s + f = 60. Substituting the first equation into the second equation produces 3f + f = 60. Combining like terms, we get 4f = 60. Dividing both sides by 4, we get f = 15. Substituting that value into the equation s = 3f, we get s = 3 * 15 = 45.. The answer is: 45.