IBM
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Logical Reasoning
Number Series
Q. Waht is the next number of the following sequences
1. 100,98,95,90,83
2. 1,1,3,1,5,3,4,10,4,2
3. 7,9,11,6,11,8,5,13,5,4,15
4. 2,7,36,4,14,225,6,21
5. 2/3,5/3,19/6,31/6,23/3,32/3,84/6
6. 12,22,35,68,15,28,31
7. 36,56,96,156
8. 3,8,12,48,29
9. 48,24,35,7,16,8,7,15,80
10. if there are 10 members in a party how many shake hands were possible altogether?
Read Solution (Total 34)
-
- 5) ans
2/3+1=5/3, 19/6+2=31/6, 23/3+3=32/3, 84/6+4=108/6 ans
6) 12*2-2=22, 35*2-2=68 .............31*2-2=60 ans
- 11 years agoHelpfull: Yes(18) No(1)
- 9)I guess the correct series is
48,24,35,7,16,8,75,15,80
Alternately divide the digits with 2 and 5
48/2=24
35/5=7
16/2=8
75/5=15
80/2=40 =>Ans=40 - 11 years agoHelpfull: Yes(18) No(0)
- 1)difference in term is
100-98=2
98-95=3
95-90=5
90-83=7
2,3,5,7 all are prime number next prime number is 11
so next term=83-11=72 ans
2)
3)break in 3 series
1.7,6,5,4(difference -1in all term )
2.9,11,13,15(diff +2)
3.11,8,5,??(diff -3)
so next term =5-3=2 ans
4)break in 3 part
1.2,4,6,8...(+2)
2.7,14,21....(+7)
3.36,225,??
next term is (15+9)^2=576
7)difference is
56-36=20
96-56=40
156-96=60
so difference increase by 20 so difference in next term is 80
156+80=236 ans
10) every persan shake hand with 9 person
so total =9*10/2=45
(divide by 2 bcz in 1 hand shake 2 person participate )
ans-45 - 11 years agoHelpfull: Yes(17) No(2)
- 8) (1^2)+2=3,(2^2)*2=8,(3^2)+3=12,(4^2)*3=48,(5^2)+4=29,(6^2)*4= 144(ans)
- 11 years agoHelpfull: Yes(14) No(0)
- 10> formula is n(n-1)/2 so ans is 10*(10-1)/2 = 45
- 11 years agoHelpfull: Yes(8) No(1)
- 6.(12-1)*2=22,(35-1)*2=68,(15-1)*2=28,(31-1)*2=60
ans=60 - 11 years agoHelpfull: Yes(7) No(0)
- 6)diff b/w 12 and 15=+3
22 and 28=+6(dauble of +3)
35and 31=-4
so diff b/w 68 and next term =-8(dauble of +4)
text term=68-8=60 ans - 11 years agoHelpfull: Yes(6) No(4)
- 2, 8 n 9??????? :(
- 11 years agoHelpfull: Yes(5) No(1)
- 3. 7,9,11,6,11,8,5,13,5,4,15
3rd 6th 9th 12th
11 8 5 2
distance 3 - 11 years agoHelpfull: Yes(4) No(1)
- 9)i think the ans is 40
take 2 pairs after 2 pairs-(48,24)(16,8) (80,?)
here 48/2=24 16/2=8 then 80/2=40. - 11 years agoHelpfull: Yes(4) No(0)
- 1)100-2=98,98-3=95,95-5=90,90-7=83,83-11=72(from each number commencing next higher prime number is added).
3){(7,9,6)-(1,-2,3)=(6,11,8)},{(6,11,8)-(1,-2,3)=(5,13,5)},{(5,13,5)-(1,-2,3)=(4,15,2)}.subtract 1 from 1st number,add 2 to second number and subtract 3 from 3rd number from each triplet respectively.hence the answer is 2.
4)2*2=4,7*2=14,(square root of 36 +9)^2=225,2*3=6,7*3=21,(square root of 36+9*2)^2=576.hence answer is 576.
5)5/3-2/3=1,31/6-19/6=2,32/3-23/3=3,108/6-84/6=4.hence answer is 108/6.
6)divide into pairs first.now 12-1=11*2=22,35-1=34*2=68,15-1=14*2=28,31-1=30*2=60.hence the answer is 60.
7)56-36=20,96-56=40,156-96=60,236-156=80.hence the answer is 236.
8)
9)48/2=24,35/5=7,16/2=8,75/5=15,80/2=40.instead of 7 there will be 75.alternately divide by 2 and 5.hnce the answer is 40.
10)10C2=45. - 11 years agoHelpfull: Yes(3) No(0)
- 5.108/6
break series into two(2/3,5/3)(19/6,31/6)(23/3,32/3),(84/6,114/6)
+1 +2 +3 +4 - 11 years agoHelpfull: Yes(3) No(0)
- 2) in sereies jst go through second 1 then skip two integer and continue the sequence.... u will see 1 _ _ 5 _ _10 _ _ 15. So 15 is the ans
- 11 years agoHelpfull: Yes(2) No(10)
- 1. 100,98,95,90,83
100-98=2
98-95=3
95-90=5
90-83=7
83-X=11
put the value of X is 72
83-72=11
so ans is 72
all number prime no . 2,3,5,7,11,..
7. 36,56,96,156
4*9=36
4*14=56
4*24=96
4*39=156
4*X=236
the distane of 14-9=5,24-14=10,39-24=15,X-39=20
so put the value of X is 59
4*59=236
- 11 years agoHelpfull: Yes(2) No(0)
- 2)1*1+2=3
1*5-2=3
3*4-2=10
4*2+2=10
ans is 10
it repeats 2 digit as same value - 11 years agoHelpfull: Yes(2) No(7)
- 3. (7,9,11),(6,11,8),(5,13,5),(4,15,X)
1st term of every sequence: (7-6=1),(6-5=1),(5-4=1)
2nd term: (9+2=11),(11+2=13),(13+2=15)
3rd term: (11-3=8),(8-3=5),(5-3=x)
therefore, x=2. - 10 years agoHelpfull: Yes(2) No(0)
- can any one explain me 2nd one
- 11 years agoHelpfull: Yes(1) No(1)
- 8) 3*4=12
8*6=48
29*8=232
Ans is 232
- 11 years agoHelpfull: Yes(1) No(13)
- 10)45
10C2
10!/8!*2! - 11 years agoHelpfull: Yes(1) No(0)
- 5)
4/6 , 10/6 , 19/6,31/6,46/6,64/6,84/6,108/6
difference on nemrator is 3 from 6,9,12.....
108/6 = 54/6 ans
- 11 years agoHelpfull: Yes(1) No(0)
- I have a question about number 4. I have read that two solutions indicate 576 as the next number. I understand the reasoning behind it. But for example, why couldn't it be 36=(2^2)*(3^2) and 225=(3^2)*(5^2) and so the next one would be (5^2)*(7^2)=1225? Is it just because the other two sub-series go without primes but with *2,*3... and so on?
- 11 years agoHelpfull: Yes(1) No(0)
- 10)10c2
10!(10-2)!*2!=45 - 10 years agoHelpfull: Yes(1) No(0)
- 2)
1,1,3
1+1=2,2+1=3
2,1,5
2+1=3,3+2=5
3,4,10
3+4=7,7+3=10
4,2,?
4+2=6,6+4=10
ans:10 - 7 years agoHelpfull: Yes(1) No(0)
- 1>100-98 =2
98-95=3
95-90=5
90-83=7
all diff primes so next will be 72 so that
83-72=11 - 11 years agoHelpfull: Yes(0) No(1)
- 6)12*2=24-2(22)
35*2=70-2(68)
15*2=30-2(28)
31*2=62-2(60) - 11 years agoHelpfull: Yes(0) No(2)
- ans for 2,9?
- 11 years agoHelpfull: Yes(0) No(1)
- can any one explain me 2nd and 9th one
- 11 years agoHelpfull: Yes(0) No(1)
- 6)(12*2)-2=22
(35*2)-2=68
(15*2)-2=28
(31*2)-2=60 ans is 60 - 11 years agoHelpfull: Yes(0) No(0)
- 6.. (12+22+35)=68
(15+28+31)=74..
so ans is 74.. - 11 years agoHelpfull: Yes(0) No(0)
- 8)there is a sequence of 4,16,64,256....
3*3-1=8
3*4=12
3*16=48
3*10-1=29
so next two nos are
3*64=192
3*256=768
then 3+7=10
10+7=17
so the next no is
3*17-1=50
so ans is 192 - 11 years agoHelpfull: Yes(0) No(3)
- As raman ojha said the last but one should be 85/6. i think typing wrong or question was asked to findout the odd man out.
- 11 years agoHelpfull: Yes(0) No(0)
- 1*1+3=4/2=2
1*5+3=8/2=4
10*4+2=42/2=21 - 9 years agoHelpfull: Yes(0) No(0)
- 2.(1,1,3),(1,5,3),(4,10,4),(2,x,y)
X=15 - 8 years agoHelpfull: Yes(0) No(0)
- i think number 2 series is wrong the real series should be like this
1, 1, 3, 2, 1, 5, 3, 4, 10, 4, 2, ?
Ans:The next number is 10.
Let take the given numbers in 3*3 matrix form.
1 1 3
2 1 5
3 4 10
4 2 x
=> 1st number + 2nd number + 1st number = 3rd number.
1 + 1 = 2
2 + 1 = 3
1 + 1 = 3
3 + 2 = 5
3 + 4 = 7
7 + 3 = 10
Similarly
4 + 2 = 6
6 + 4 = 10.
Therefore, the series is 1, 1, 3, 2, 1, 5, 3, 4, 10, 4, 2, 10. - 8 years agoHelpfull: Yes(0) No(0)
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