5272道题目5525 条题源记录 · 相同内容已合并
线性建模・建立方程进阶
A boat traveled a certain distance upriver and then traveled downriver 10 miles farther than it traveled upriver. The boat took \( x \) hours to travel upriver at a speed of 12 miles per hour. The boat then took \( y \) hours to travel downriver at a speed of 18 miles per hour faster than the speed at which the boat traveled upriver. Which of the following equations best represents this situation?
原库参考解析
线性建模・建立方程挑战
A business owner purchased an energy-efficient air conditioning system for a cost of $4,200, including installation. The business owner saves $940 per year to operate the new system compared to the operating cost of the old system. Including the cost of the new system, which function \( f \) gives the total amount, in dollars, the business owner has saved \( x \) years after purchasing the new system?
原库参考解析
线性建模・建立方程挑战
A machine makes 8-inch, 5-inch, and 7- inch parts. During a certain day, the number of 8-inch parts that the machine makes is 3 times the number n of 5-inch parts, and the number of 7-inch parts is 12. During this day, the machine makes 100 parts total. Which equation represents this situation?
原库参考解析
线性建模・建立方程挑战
A beekeeper's initial observation of the population of a certain bee colony was 1,100 bees. The beekeeper set a goal to increase the population to 2,600 bees. The beekeeper uses a model that predicts the population of this bee colony begins at 1,100 and increases by 120 bees per week in the first two weeks after the initial observation, and then increases by 180 bees per week until the beekeeper’s goal is reached. According to this model, at the end of week w after the initial observation, where \( w>2 \) , which of the following functions gives the predicted number of bees still needed to reach the beekeeper’s goal?
原库参考解析
线性建模・建立方程进阶
Carrie has c dollars and Marjani has m dollars. Carrie has 4 times as many dollars as Marjani, and together they have a total of $40.00. Which system of equations represents this situation?
原库参考解析
线性建模・建立方程挑战
A book-of-the-month club charges $16 for the first book purchased during the month and an additional $11 for each book after the first. Which equation describes this situation, where y is the total cost, in dollars, for books purchased during a month, x is the number of books purchased during the month, and \( x>0 \)?
原库参考解析
线性建模・建立方程挑战
Micah deposited a total of $6,600 into two retirement accounts last year by depositing x dollars once each month into one account and y dollars twice each month into the other account. Which equation represents this situation?
原库参考解析
线性建模・建立方程挑战
A book-of-the-month club charges $16 for the first book purchased during the month and an additional $12 for each book after the first. Which equation describes this situation, where y is the total cost, in dollars, for books purchased during a month, x is the number of books purchased during the month, and \( x>0 \) ?
原库参考解析
线性建模・建立方程挑战
Ellie deposited a total of $4,300 into two retirement accounts last year by depositing x dollars once each month into one account and y dollars twice each month into the other account. Which equation represents this situation?
原库参考解析
线性建模・建立方程挑战
A store sells bottles of water for $0.93 each and makes a profit of $0.35 on each bottle sold. During the first three days of a week, the store sold 128 bottles of water. The rest of the week, the store sold w bottles of water. The store made a total profit of $130.20 from selling bottles of water during the week. Which equation represents this situation?
原库参考解析
线性建模・建立方程进阶
There are a total of 1,200 milligrams of phosphorus in a sample of soil. Each kilogram of this sample contains 600 milligrams of phosphorus. Which equation represents this situation, where x is the mass, in kilograms, of the sample of soil?
原库参考解析
线性建模・建立方程挑战
The cost to rent a kayak consists of a fixed fee for the first hour and an hourly fee for each additional hour. The table shows the rental cost for 4 hours and for 6 hours.
Which function f gives the rental cost, in dollars, for x hours rental, where \( x\ge1 \)?
原库参考解析
