#### 题目列表

The population of City X in 1999 was r percent greater than it was in 1990, and the average income per person in 1999 was i percent greater than it was in 1990. The percent increase in the total income of the entire population from 1990 to 1999 would have been greatest for which of the following values of r and i?
Yesterday a certain merchant had $1,285.00 in total sales. If $\frac{1}{2}$ of the total sales were from the sale of merchandise that had been reduced by 50 percent, what would have been the total sales yesterday if all of the merchandise had been sold at full price? At a furniture store on Monday, the retail price of a table was n dollars. On Wednesday that week, the retail price of the table was reduced to$56. On Friday that week, the price of table was reduced again to 25 percent less than the price on Wednesday. If the ratio of n to the price of the table on Friday is 32 to 21, what is the value of n?
Last year Leo bought two paintings. This year he sold them for $21,000 each. On one, he made a 25% profit, and on the other he had a 25% loss. What was his net loss or profit?$_____
On the first day, the ticket price of a concert is 15% less than the original price; on the second day, the ticket price of the concert continued to drop by 20% than the first day. What percent is the price of the ticket on the second day less than the original price?

_____%
For each of the years 1993 and 1994, the population of City M increased by 20 percent during the year. If the population was 280,000 on December 31, 1994, approximately what was the population on January 1, 1993?
y=2x+1, where x > 0.

#### Quantity A

The percent increase in the value of y when the value of x is increased by 10%

#### Quantity B

10%

Three variables, x, y, and z, in a scientific experiment are related by the equation $z=x^{2}y$. In the experiment, if the value of x decreases by 40 percent while the value of y increases by 50 percent, what is the percent decrease in the value of z?
The total revenue that firm P receives from the sale of a particular item is determined by multiplying the number of the items it sells by the price of the item. If the price of the item is to be decreased by 20 percent, by what percent must the number of the items sold increase to keep the total revenue unchanged?
Evelyn owns two different properties with areas of 1.5 acres and 0.5 acre, respectively. What is the total area, in square feet of the two properties combined? (1 acre = 4,840 square yards, 1 yard = 3 feet)

_____square feet
1 yard=3 feet

1 acre=4840 square yard

#### Quantity A

One acre when transformed in terms of square feet

#### Quantity B

40,000

The area of a certain floor is 150 square feet. (1 yard=3 feet)

#### Quantity A

The area of the floor, in square yards

#### Quantity B

30

1 cup=8 ounces

1 pint=2 cups

1 quart=2 pints

A large coffee jug contains 3 quarts, 1 pint, and 1.5 cups of coffee. What is the greatest number of 12-ounces mugs of coffee that can be filled from the jug?
A certain store sells circular rugs at a constant price per square foot. If a circular rug with diameter 5 feet costs \$250, what is the cost of a circular rug with diameter 9 feet?
After a bird feeder was filled with x pounds of birdseed, 12 ounces of birdseed were consumed each day for the next 8 days. (1 pound=16 ounces)

#### Quantity A

At the end of the 8 days, the weight of the birdseed in the bird feeder that was not consumed

#### Quantity B

x-5 pounds

The length of a model car is 8.2 centimeters, and the ratio of the length of the model car to the length of the actual car that it represents is 1 to 64. The length of the actual car is how many meters? (1 centimeter=0.01 meter)

_____meters
To fill a cube, machine A needs 5 hours. If machine A and B together fill the cube, it will take $\frac{1}{3}$ of the time if machine B fills the cube alone. How many hours will it take if B fill the cube alone?

_____hours
It takes machine A 2 minutes to fill a cube whose volume is $50m^{3}$ with water. If the cube holds $10m^{3}$ of water at first, and then machine A works for 1.5 minutes. By then, what percent of the cube is filled with water?

_____%
By draining 40 gallons of water from a tank, the amount of water in the tank was decreased from $\frac{1}{5}$ of the tank 's full capacity to $\frac{2}{11}$ of the tanks full capacity. Water was then added to the tank until the tank was full. How many gallons of water were added to the tank?
The overall volume of a water tank is g. If the inlet valve is open for a minute, x volume of water will be added to the tank; If the discharge valve is open for a minute, y volume of water will be removed from the tank (y>x). If the tank is filled with water at first, then in how many minutes will the water volume in the tank drop to a half if the inlet valve and discharge valve are both open?