Wordproblems appearing on the GRE

[awuah29]

anyone knows how to set up those problems. much help appreciated

1.If : x2 –8x = (x-4)/3. What is a value for x that makes this statement true?

2.A worker at an apple orchard is paid $ 15.00 per dozen for the first dozen apples he picks and $ 18.00 per dozen after that. If he picks 78 apples total, then how much will he be paid?

3. Tucker purchased a stock that immediately increased in value by 50%. Th next week it depreciated by 20% and sold the stock for $ 120,000. What was the original purchase price of the stock?

4. If x is positive and x is not equal to zero and y is not equal to zero, then all of the following are the negative except which one.

A. –xy4
B. xsin(5pi/4)
C. –xcos(pi/3)
D. –(xy)2
E. xcos(2pi)


5 If a and b are prime numbers and a x b =x then which of the following could equal x?

A. 23 B. 12 C. 86 D. 77 E. 54

[Cipochka]

1.
x^2-8x=(x-4)/3
3x^2-24x=x-4
3x^2-25x+4=0

x1=(-b-sqv(b^2-4ac))/2a=(25-sqv((-25)^2-4*3*4))/2*3=0.163
x2=(-b+sqv(b^2-4ac))/2a=(25+sqv((-25)^2-4*3*4))/2*3=8.17


2. 78/12=6.5
15+5.5*18=114$

3. (x*1.5)*0.8=120
x=120/0.8/1.5=100$

4. E

5. D
77=7*11

[lime]

Originally Posted by Cipochka

5. D
77=7*11

C. 86=43*2