Posted: Fri Jul 21, 2006 11:29 am Post subject: number system problems
1.find the number of numbers between 200 and 300, both included, which are not divisible by 2,3,4 and 5
a)27 b)26 c)25 d)none
2.the mean of 1,2,2^2…..2^31 lies in between
a)2^24 to 2^25 b)2^25 to 2^26 c)2^26 to 2^27 d)2^29 to 2^30
3.if AB+XY=1XP,where A is not equal to 0 and all the letters signify different digits from 0 to 9, then the value of A is:
a)6 b)7 c)9 d)any value above 6
4.[x] denotes the greatest integer value just below x and {x} its fractional value. The sum of [x]^2 and {x}^1 is 25.16.find x
a)5.16 b)-4.84 c)both a and b c)cant b determined
5.find the number of zeros in the product: 1^1*2^2*3^3*4^4*…..98^98*99^99*100^100
a)1200 b)1300 c)1050 d)none
Posted: Thu Apr 12, 2007 6:05 pm Post subject: number system problem 3
hi,
3.) i think answer is 9
As carry from addition of unit's digits can't be more than 1 ,
and X remains X after adding ten's digits ,this means that A plus 1(carry) should be equal to 10 ,so that x remains x ,
hence A can be 9 only.
Posted: Tue Nov 13, 2007 7:25 pm Post subject: Re: number system probsssssss
palagg wrote:
1.find the number of numbers between 200 and 300, both included, which are not divisible by 2,3,4 and 5
a)27 b)26 c)25 d)none
find the number of numbers that are divisible by 2, 3, 4, 5 between 200 and 300 and then subtract that from 101 (101 numbers between 200 and 300 both included)
numbers divisible by 2, 3, 4, 5 will belong to the set AUBUCUD, where A is the set of numbers divisible by 2, B by 3, C by 4 and D by 5.
AUBUCUD = A + B + C + D - (AnB + BnC + CnD + BnD + AnC + AnD) + (AnBnC + AnCnD + BnCnD + AnBnD) - AnBnCnD.
A has 51 elements including 200 and 300
B has 34 elements including 300
C has 26 elements including 200 and 300
D has 21 elements including 200 and 300
AnB has 17 elements including 300 (every 6th number will be divisible by 2 and 3)
BnC has 9 elements including 300
CnD has 6 elements including 200 and 300
BnD has 7 elements including 200 and 300
AnC has 26 elements including 200 and 300
AnD has 11 elements including 200 and 300
AnBnC has 9 elements including 200 and 300
AnCnD has 6 elements including 300
BnCnD has 2 elements including 300
AnBnD has 4 elements including 300
