【官方指南】新GRE数学真题OG例题讲解之函数题型

1.y=2x2+7x – 3

x       y

2.

The figure above shows the graph of a function f, defined by f(x)=|2x|+4 for all numbers x. For which of the following functions g defined for all numbers x does the graph of g intersect the graph of f ?

A g(x) x–2

B g(x) x 3

C g(x) 2x – 2

D g(x) 2x 3

E g(x) 3x – 2

3.Each employee of a certain company is in either Department X or

Department Y, and there are more than twice as many employees in Department X as in Department Y. The average (arithmetic mean) salary is $25,000 for the employees in Department X and is $35,000 for the employees in Department Y. Which of the following amounts could be the average salary for all of the employees in the company?

Indicate all such amounts.

A $26,000

B $28,000

C $29,000

D $30,000

E $31,000

F $32,000

G $34,000

4.Working alone at its constant rate, machine A produces k car parts in 10 minutes. Working alone at its constant rate, machine B produces k car parts in 15 minutes. How many minutes does it take machines A and B, working simultaneously at their respective constant rates, to produce k car parts?

____________minutes

5.

1)If the dollar amount of sales at Store P was $800,000 for 2006, what was the dollar amount of sales at that store for 2008 ?

A $727,200

B $792,000

C $800,000

D $880,000

E $968,000

2)At Store T, the dollar amount of sales for 2007 was what percent of the dollar amount of sales for 2008 ?

Give your answer to the nearest 0.1 percent.

___________%

3)Which of the following statements must be true?

Indicate all such statements.

B –1 3

C 0 3

D 1 3

each of the other four stores.

B The dollar amount of sales at Store S for 2008 was 22 percent less than that for 2006.

C The dollar amount of sales at Store R for 2008 was more than 17 percent greater than that for 2006.

6.A certain store sells two types of pens: one type for $2 per pen and the other type for $3 per pen. If a customer can spend up to $25 to buy pens at the store and there is no sales tax, what is the greatest number of pens the customer can buy?

E 20

7.A list of numbers has a mean of 8 and a standard deviation of 2.5. If x is a number in the list that is 2 standard deviations above the mean, what is the value of x ? x=______