Search found 44 matches
Let the number be ABC We MUST have 2 and 6 in this number. So first let's see how many ways we can do that. Split the problem into 2 parts: 1. How many ways can we arrange these two digits 2 and 6 which must compulsorily be there, into 3 different places, where position/order matters? 2. How many w...
- by rooster
Mon Dec 05, 2011 5:42 pm- Forum: Problem Solving
- Topic: 3 digit number
- Replies: 12
- Views: 4042
Think of it like this: A^5 + A^5 + B^5 + B^5 + B^5 Even though we are dealing with exponents, the exponent does not change. Therefore, we get this as a result: 2(A^5) + 3(B^5) In any other scenario, that is it. But, for this equation, A happens to be 2, and B = 3. 2(2^5) is the same as saying 2(2*2*...
- by rooster
Tue Nov 22, 2011 2:05 am- Forum: Problem Solving
- Topic: Which of the following is equal to 2^5+2^5+3^5+3^5+3^5 ?
- Replies: 6
- Views: 8508
Doesn't this mean that the two lines are part of x=3y-7?
I just solved for y and then plugged in numbers.
Since we know y= x/3 + 7/3
I made x = 2 and then solved for the problem if x was +3, which resulted in y making a change from 3 to 4 equal to 1, the change of y.
- by rooster
Tue Nov 22, 2011 1:35 am- Forum: Problem Solving
- Topic: xy coordinate system??
- Replies: 4
- Views: 1418
Two ways other than plugging in. 1. Solve for zero: x(2x+1)=0 and (x + 1/2)(2x - 3)=0, then x =? In the first equation, you know x= 0 or 2x+1=0, x=-1/2 In the second, in order for it to be zero, x needs to be -1/2 or 3/2. In order for a term to satisfy both equations, x=-1/2. OR Since you know the t...
- by rooster
Mon Nov 21, 2011 11:07 pm- Forum: Problem Solving
- Topic: What does x =? Helpp!
- Replies: 7
- Views: 2899
- by rooster
Mon Nov 14, 2011 2:56 am- Forum: Problem Solving
- Topic: Decimals
- Replies: 6
- Views: 1327
Hi, Im unable to understand OG-12's explanation for this specific question. Can anyone please elaborate a simpler way to solve it?! If p is the product of the integers from 1 to 30 ,inclusive, what is the greatest integer k for which 3k is a factor of p ? (A) 10 (B) 12 (C) 14 (D) 16 (E) 18 If it's ...
- by rooster
Sun Nov 13, 2011 7:41 pm- Forum: GMAT Math
- Topic: OG-12 Number Properties Question
- Replies: 2
- Views: 1211
Need to figure out what the question is asking, which is "how many threes are in 21!"? so, you can list out like this 21 - (3) 18 - (3,3) 15 - (3) 12 - (3) 9 - (3,3) 6 - (3) 3 - (3) By this, we know we have a total of nine 3s Now, with that said, we need to see if either can fulfill this. ...
- by rooster
Sun Nov 13, 2011 7:14 pm- Forum: GMAT Math
- Topic: factorial ds
- Replies: 5
- Views: 1855
sorry my mistake it says what is the greatest integer m for which N/10^m is an integer? N/10^m = Integer N =3*9*12* 15 *...30*..45*..60*..75*..90. So N contains 5^7 and 2^n where n > 7 N/10^m = X*5^7*2^n/10^m The maximum value of m = 7 IMO C Right approach, but I don't see how you get 7 5's Basical...
One point to keep in mind as you approach this problem: Even if n=negative, the negative sign in front still changes the status therefore even if n= -1 -n= 1 OR -(-1) Just need to know the properties as neelgandham pointed out the options. in order for xyz to be >0, all are negative or either 2 of t...
- by rooster
Wed Oct 26, 2011 2:25 am- Forum: Problem Solving
- Topic: Number Properties!
- Replies: 3
- Views: 884
x(x- (5x+6/x) ) = 0. Should have been written as : x(x- {(5x+6)/x)} ) = 0. Now x *(x ^2 -5x -6)/ x = 0 we can simplify it to (x ^2 -5x -6) = 0 which gives soln as x = 6 or -1 basic quadriatic eqn. "Now x *(x ^2 -5x -6)/ x = 0" - How do you get rid of the x outside the parentheses? the X a...
- by rooster
Tue Oct 25, 2011 9:29 pm- Forum: Problem Solving
- Topic: solving for x, distribution of x...need help please
- Replies: 5
- Views: 1484
Please could you explain how does it implies mn = 2 * 3 * (5^2) = 150 from 2^3 * 3^3 * 5^2 * mn = k^4 Since 5400mn = k^4, so 2, 3, and 5 should be all 4th powers 2^3 * 3^3 * 5^2 * mn = k^4 implies mn = 2 * 3 * (5^2) = 150 , which is the least value of mn. There are a few hints that will let us know...
- by rooster
Tue Oct 25, 2011 9:14 pm- Forum: Problem Solving
- Topic: If 5400mn = k^4
- Replies: 4
- Views: 1989
Integer m has 4 different prime factors and n has 3 different prime factors. If m and n has the greatest common factor of 15, how many different prime factors does mn have? As the GCF of m and n is 15 = 3*5, m and n both must have 3 and 5 as their prime factors. Hence, the other two prime factors o...
- by rooster
Tue Oct 25, 2011 6:50 pm- Forum: Problem Solving
- Topic: Prime factors.
- Replies: 7
- Views: 2422
I can not understand why X can not be 10, Pleas, explain more on this It says that x is between 5 and 11, we also need to know what numbers can be broken down into primes. 88,000 = (11)(10^3)(8) OR (11)(2*2*2*5*5*5)(2*2*2) Since we know 5 is one of the chips, we can take 5 out of the equation, and ...
- by rooster
Tue Oct 25, 2011 5:35 pm- Forum: Problem Solving
- Topic: More Primes
- Replies: 93
- Views: 45610
Three grades of Milk are 1%,2% and 3% fat by Vol. If x gallons of 1% grade, y gallons of 2% grade and z gallons of 3% grade are mixed to give x+y+z gallons of 1.5% grade.What is x in terms of y and z ? a. y+3z b. 2y+3z c. 3y+4.5z d. (y+z)/4 e. 3y+z OA - a. y +3z Plz explain... Combining equal amoun...
- by rooster
Wed Oct 12, 2011 10:38 pm- Forum: Problem Solving
- Topic: MIXTURESS
- Replies: 7
- Views: 1684