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1) as x = 4n+2, assuming n an integersud21 wrote:Is 3x+1 divisible by 10?
1) x = 4n+2
2) x > 4
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we have 3(4n+2) + 1 = 12n+7
this will not be divisble by 10 since 12n+7 will always be an odd integer. hence suff.
2)x>4
3x+1 can be or cannot be divisible 10. so insuff.
user123321
- by user123321
Fri Jan 13, 2012 6:33 am- Forum: Data Sufficiency
- Topic: number properties
- Replies: 2
- Views: 923
- by user123321
Fri Jan 13, 2012 6:28 am- Forum: Data Sufficiency
- Topic: number properties
- Replies: 14
- Views: 1657
A people walked from signpost 1 to signpost 2 at the average rate of 0.125km/m. Is the distance between two signposts greater than 0.8km? 1). It cost more than 400 second for the people finish the trip 2). It cost less than 450 second for the people finish the trip. source search engines [spoiler]I...
- by user123321
Fri Jan 13, 2012 6:23 am- Forum: Data Sufficiency
- Topic: word problem
- Replies: 1
- Views: 828
R and S are integers, is R/S a finite decimal? 1). R is the factor of 100 2). S is the factor of 100 1) has no info about S. hence insuff. 2) has no info about R. hence insuff. using both, still we cannot determine whether it is finite decimal or not. because for example, R can be 200 and S can be ...
- by user123321
Fri Jan 13, 2012 6:19 am- Forum: Data Sufficiency
- Topic: number properties
- Replies: 7
- Views: 1238
since r,s are roots of the equation and product of roots is c, the question is asking whether c<0 or not?sud21 wrote:If r and s are root of x^2+bx+c=0, rs<0?
1). b<0
2). c<0
1) insuff.
2) suff.
user123321
- by user123321
Fri Jan 13, 2012 6:16 am- Forum: Data Sufficiency
- Topic: number properties
- Replies: 1
- Views: 844
- by user123321
Thu Jan 12, 2012 10:10 pm- Forum: Data Sufficiency
- Topic: number properties
- Replies: 9
- Views: 1129
Hisud21 wrote:Integer x is greater than 0, is x a prime number?
1). All the prime factors of x are greater than root x
2). All the prime factors of x are greater than x/2
I think there is some issue in the problem.
a prime factor of x cannot be b/w root x and x.
please check once.
Regards,
user123321
- by user123321
Thu Jan 12, 2012 6:09 pm- Forum: Data Sufficiency
- Topic: number properties
- Replies: 9
- Views: 1129
What is the median of numbers 4,5,6,7,9, and x? 1). X>7 2). The mean of the six numbers is equal to the median. 4,5,6,7,9,x 1) x > 7 => x will be greater than 7. so this will not change the median which is (6+7)/2 = 6.5 hence suff. 2) mean of six numbers is equal to median. => median = (31+x)/6 = 5...
- by user123321
Thu Jan 12, 2012 2:22 pm- Forum: Data Sufficiency
- Topic: statist
- Replies: 1
- Views: 732
- by user123321
Thu Jan 12, 2012 12:53 pm- Forum: Data Sufficiency
- Topic: number properties
- Replies: 14
- Views: 1657
@user123321 nope D is ok. stmnt 1 is good enough to find the answer. p.s. my fault. i misunderstood the q.stem 1st, and thought that we should find the average speed of two cars. I am sorry, I am still not understanding :( I think in 1) we just know the speed for first 30 minutes. what after that i...
- by user123321
Thu Jan 12, 2012 12:47 pm- Forum: Data Sufficiency
- Topic: word problem
- Replies: 10
- Views: 1223
There is a car and a truck, in the same duration, car traveled 120 miles, and truck traveled 100 miles. What is the average speed of truck in this period? 1) In the first 30 min, car traveled 30 miles. 2) The average speed of the car is 10 miles/hour more than the truck. 1) since we dont know car's...
- by user123321
Thu Jan 12, 2012 11:42 am- Forum: Data Sufficiency
- Topic: word problem
- Replies: 10
- Views: 1223
seems like there is some issue in the question.sud21 wrote:There is a set of number, the mean is m, the standard deviation is R, if add a number x to this set, is r<= R?
1) x=m
2) m<x<m+R
what does r refer to?
user123321
- by user123321
Thu Jan 12, 2012 11:35 am- Forum: Data Sufficiency
- Topic: statist
- Replies: 2
- Views: 813
There is a car and a truck, in the same duration, car traveled 120 miles, and truck traveled 100 miles. What is the average speed of truck in this period? 1) In the first 30 min, car traveled 30 miles. 2) The average speed of the car is 10 miles/hour more than the truck. 1) since we dont know car's...
- by user123321
Thu Jan 12, 2012 11:26 am- Forum: Data Sufficiency
- Topic: word problem
- Replies: 10
- Views: 1223
Is the standard deviation of a set 0? 1). The average is equal to the greatest number. 2). The median is equal to the average number. 1) average equals greatest number => all numbers are same. so SD = 0. hence suff. 2) median = avg. lets take simple example 1,2,3. here SD != 0 and if numbers are 1,...
- by user123321
Thu Jan 12, 2012 10:50 am- Forum: Data Sufficiency
- Topic: statist
- Replies: 1
- Views: 770
X=2.543*10^K, where k is an integer, what is the thousandth digit of x? 1). The hundredth digit of x is 0 2). Hundredth digit minus thousandth digit is 3 1) hundredth digit of x is 0. we dont know anything about k whether it is +ve or -ve. so insuff. 2) this can happen only when k = 1 then 3-0 = 3....
- by user123321
Thu Jan 12, 2012 10:46 am- Forum: Data Sufficiency
- Topic: number properties
- Replies: 4
- Views: 1103