Search found 11 matches
bjp2008 wrote:I also get 7.tdadic84 wrote:i also get 7...please confirm ur answer
- my bad, it is 7. sorry everyone.
- by kevind147
Sun May 17, 2009 7:32 pm- Forum: Problem Solving
- Topic: Greatest prime factor?
- Replies: 4
- Views: 1406
Greatest prime factor?
What is the greatest prime factor of 4^17-2^28?
a. 2
b. 3
c. 5
d. 7
e. 11
The answer is e ... how?
- by kevind147
Sat May 16, 2009 8:23 am- Forum: Problem Solving
- Topic: Greatest prime factor?
- Replies: 4
- Views: 1406
thanks this makes the most sense to me, but why is the series multiplied by 2? Why is it 2(2^8-1) instead of just (2^8-1)?scoobydooby wrote:2+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8
=2+(2+2^2+2^3+2^4+2^5+2^6+2^7+2^8)
=2+[sum of GP with common ratio 2, n=8; a(r^n-1)/(r-1)]
=2+2(2^8-1)/(2-1)
=2+2(2^8-1)
=2+2^9-2
=2^9
- by kevind147
Sat May 16, 2009 8:18 am- Forum: Problem Solving
- Topic: exponents
- Replies: 6
- Views: 1434
exponents
from a practice test:
2+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8=?
a. 2^9
b. 2^10
c. 2^16
d. 2^35
e. 2^37
I got e., but the answer is a. Why?
- by kevind147
Sat May 16, 2009 8:00 am- Forum: Problem Solving
- Topic: exponents
- Replies: 6
- Views: 1434
I agree, I'm using it now and it's a great "workout" but a lot of the questions are more drills than GMAT questions.
- by kevind147
Fri Apr 24, 2009 6:59 am- Forum: GMAT Strategy
- Topic: Bob miller's math for the gmat
- Replies: 2
- Views: 2180
good lord, that was fast. i told you it was easy! thanks guys! i need to learn to look at this stuff from different angles ...
- by kevind147
Wed Apr 22, 2009 10:11 am- Forum: Problem Solving
- Topic: Easy factoring question
- Replies: 3
- Views: 1034
Easy factoring question
Can someone walk me through factoring this:
x^4 - 10x^2 + 9
The answer is (x+3)(x-3)(x+1)(x-1), but I don't know how to get there.
- by kevind147
Wed Apr 22, 2009 9:48 am- Forum: Problem Solving
- Topic: Easy factoring question
- Replies: 3
- Views: 1034
Is this assumption correct?
If X/Y = 2/3, what is the value of (X-Y)/X?
A. -1/2
B. -1/3
C. 1/3
D. 1/2
E. 5/2
The answer in the book gives a long drawn-out explanation, but can you not just assume that X = 2 and Y = 3 from the equation provided? So (2-3)/2 = -1/2. Is this assumption correct?
- by kevind147
Mon Mar 30, 2009 9:59 am- Forum: Problem Solving
- Topic: Is this assumption correct?
- Replies: 9
- Views: 1823
earnings question
114. Salesperson A's compensation for any week is $360 plus 6 percent of the portion of A's total sales above $1,000 for that week. Salesperson B's compensation for any week is 8 percent of B's total sales for that week. For what amount of total weekly sales would both salespeople earn the same comp...
- by kevind147
Fri Mar 27, 2009 8:18 am- Forum: Problem Solving
- Topic: earnings question
- Replies: 3
- Views: 1374
- by kevind147
Thu Mar 19, 2009 10:32 am- Forum: Problem Solving
- Topic: Can't figure these out ...
- Replies: 8
- Views: 1935
Can't figure these out ...
OK I always have trouble with these kinds of questions. Here's one that I just don't get: Of 30 applicants for a job, 14 had at least 4 years' experience, 18 had degrees, and 3 had less than 4 years' experience and did not have a degree. How many of the applicants had at least 4 years' experience an...
- by kevind147
Wed Mar 18, 2009 8:18 am- Forum: Problem Solving
- Topic: Can't figure these out ...
- Replies: 8
- Views: 1935