本文发布于2019年8月26日
数学词汇-比例部分（ratio）
| 中文术语 | English | example |
|---|---|---|
| 等价分数 | equivalent fractions | 1/2↔2/4 |
| 相约减 | reducint(canceling) | 15/35→3/7 |
| 倒数 | Reciprocals | 1/2 ↔ 2/1 |
| 比较 | comparison | |
| 假分数 | improper factions | 4/3 |
| 混合分数 | mixed number | 1½ |
| 转换成小数 | converting decimals | ⅛↔0.125 |
| 转换成恩书 | converting fraction | 0.6↔⅗ |
| 四舍五入 | round | round to 2 decimal, 0.345→0.35 |
| 百分比 | percents | 3% |
- ratio
- 比例、比率 （13/25）
- rates
- based on the denominator to 1, and call per. 规划为分母等于1。比如：￥0.46/度电
- speed
- distance/time
- average
- in GRE, limited to: average = sums of terms / number of terms.
In GRE, you might be required to find the missing number by using the average.
注：中文解释部分，仅说明了该词汇在数学范围内的常用术语，不代表全部中文解释。
基础习题/Basic Exercises
- If -1 < x < 1, but x is not 0, which is greater, |x4| or |x5|?
- The ratio of red to blue to black pens in a box is 3:5:7. If all 75 pens in the box are one of these colors, how many are red?
- 17 is what percent of 85?
- If the average of 6, 3, -2, 5, 11, and x is 5, what is the value of x?
- Abdul recently made a 200 mile trip. For the first 30 miles, he traveled at an average speed of 45 MPH (miles per hour). His average speed for the next 50 miles was 60 MPH. Abdul averaged 50 MPH for the final portion of his trip. How long did it take Abdul to complete his journey?
- A certain brand and style of shoe was priced at $120. The store owner was concerned that this shoe was not selling well enough, so she decided to mark the list price down by 15%. Sales of the shoe only increased slightly, so the owner offered an additional 10% discount from the sale price at checkout. Sale tax of 8% is added to all purchases. What would a customer have to pay for the shoes with tax added?
- Jennifer and Boris are graduate assistants helping a professor grade student tests. Working together, they are able to complete the task in 1 hour and 12 minutes. If Jennifer could has graded the entire batch of tests by herself in 2 hours, how long would it have taken Boris to complete that task by himself?
Key：1、|x4|；2、15；3、20%；4、7；5、3h54m；6、$99.14；7、3h
强化训练题/Challenging Exercises
- The ratio of x to y is 1:4. If the value of x were increased by 1 without changing the value of y, the ratio of x to y would become 1:3. If z = x + 2y, what is the value of z?
- Working together, K, L and M can complete a task in 4 hours. If K alone could complete in 8 h and L could complete in half the time it would take M, how long would it take L to complete by herself?
- In a bag of coins, 2/5 are pennies, 1/3 are nickels, ¼ are dimes, and there are 5 quarters. If there are no other coins in the bag, what is the total number of coins?
- If A:B is 3:7, C:D is 15:11, and B:C is 14:5, what is A:D?
- Jack drives a car that the fuel economy readout on the dashboard is stated 1.095L/km. what is the rate stated in miles per gallon?( Note: 5mile ~= 8km, 1gallon ~= 3.8L)
Key： 1、27；2、12h；3、300；4、18:11；5、25MPG
注：本文所选词汇主要参考《GRE Prep - Graduate Record Examination》-Kaplan系列书籍。仅限于个人学习使用，请勿用于任何商业用途。