Question: Santana has 7 brothers. 3 of them have birthdays in March, 1 of them has a birthday in October, 1 has a birthday in November, and another 2 of them were born in December. If Santana always buys each of her brothers a birthday present and a Christmas present, how many more presents does she have to buy in the second half of the year than the first half of the year?
Answer with step-by-step thinking: Santana has 1 + 1 + 2 = 4 brothers with birthdays in the second half of the year. She has 7 brothers - 4 brothers = 3 brothers with birthdays in the first half of the year. Altogether, she has to buy 4 + 7 = 11 presents in the second half of the year. Therefore, she has to buy 11 - 3 = 8 more presents in the second half of the year.
So the answer is 8.

Question: Carol is an aviation engineer deciding how much fuel to put in a jet. The empty plane needs 20 gallons of fuel per mile. Each person on the plane increases this amount by 3 gallons per mile, and each bag increases it by 2 gallons per mile. If there are 30 passengers and 5 flight crew, and each person brought two bags, how many gallons of fuel does the plane need for a 400-mile trip?
Answer with step-by-step thinking: First find the total number of people by adding the number of passengers and flight crew: 30 people + 5 people = 35 people. Then find the total number of bags by doubling the total number of people: 35 people * 2 bags / person = 70 bags. Then find the fuel increase caused by the people by multiplying their number by the fuel increase per person: 35 people * 3 gallons / mile / person = 105 gallons / mile. Then multiply the number of bags by the fuel increase per bag to find the total fuel increase they cause: 70 bags * 2 gallons / mile / bag = 140 gallons / mile. Now add the fuel increases to the base fuel consumption to find the total fuel needed per mile: 140 gallons / mile + 105 gallons / mile + 20 gallons / mile = 265 gallons / mile. Now multiply the fuel consumption per mile by the number of miles flown to find the total amount of fuel needed: 265 gallons / mile * 400 miles = 106,000 gallons of fuel.
So the answer is 106000.

Question: Rookie police officers have to buy duty shoes at the full price of $85, but officers who have served at least a year get a 20% discount. Officers who have served at least three years get an additional 25% off the discounted price. How much does an officer who has served at least three years have to pay for shoes?
Answer with step-by-step thinking:
Cops that served a year pay $85 * 0.2 = $17 less. Cops that served a year pay $85 - $17 = $68. Cops that served at least 3 years get a $68 * 0.25 = $17 discount. Cops that served at least 3 years pay $68 - $17 = $51 for shoes.
So the answer is 51.