Alice's white water rafting class is composed of 40 students and 10 instructors, including herself. She has 20 life vests on hand. 20% of her students are bringing life vests. How many more life vests will Alice need to get so that entire class has one? Give the rationale and then the answer.
Let's think step by step. 20% of her 40 students will bring their own life vest so .20 * 40 = 8 students will bring their life vests. Alice has 20 life vests and 8 students will bring there's so that's 20 + 8 = 28 life vests. There are 40 students and 10 instructors total so that's 40 + 10 = 50 people in the class. If there are 28 life vests and she has 50 people then she needs to find 50 - 28 = 22 more life vests.. The answer is: 22.

Lighters cost $1.75 each at the gas station, or $5.00 per pack of twelve on Amazon. How much would Amanda save by buying 24 lighters online instead of at the gas station? Give the rationale and then the answer.
Let's think step by step. First find how many packs Amanda would have to buy on Amazon: 24 lighters / 12 lighters / pack = 2 packs. Then multiply that number by the cost per pack to find the total cost from Amazon: 2 packs * $5 / pack = $10. Then multiply the total number of lighters Amanda buys by the cost per lighter at the gas station: 24 lighters * $1.75 / lighter = $42. Then subtract the total Amazon cost from the total gas station cost to find the savings: $42 - $10 = $32.. The answer is: 32.

There are chickens roaming the chicken farm. The roosters outnumber the hens 2 to 1. If there are 9,000 chickens on the chicken farm, how many roosters are there? Give the rationale and then the answer.
Let's think step by step. There are 9000 / (2 + 1) = 3000 hens on the farm. There are 3000 * 2 = 6000 roosters on the farm.. The answer is: 6000.