Next number of the sequence will be 5, -7, 19, -21, 41, -43,.......

M4maths Previous Puzzles

02 May 2011 sequence

Next number of the sequence will be
5, -7, 19, -21, 41, -43,.......

OPtion

1) 45
2) 54
3) 59
4) 65
5) 71
6) 82
7) 89
8) 92
9) 99
10) 104

Solution

1+(2^2), 2-(3^2), 3+(4^2), 4-(5^2), 5+(6^2), 6-(7^2), 7+(8^2)

Correct Option: 5 Best Solution (7)

Dr.Dipin Singh   13 years AGO

2^2+1=5
3^2-2=7....... make it negative
4^2+3=19
5^2-4=21...... make it negative ... -21
..
..
8^2+7=71 .. option 5

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Karthick Babu   13 years AGO

2^2+1,-[3^2-2],4^2+3,-[5^2-4],6^2+5,-[7^2-6],8^2+7,...
So ans is 8^2+7=71

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Gajendra Yadav   13 years AGO

19-5=14
41-19=22 22-14=8
22+8=30
41+30=70.......Answer

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gopi uttarakavatam   13 years AGO

reason:neglect the negative sign n set1(5,7),set2 (7,19),set3 (19,21),set4(21,41),set5(41,43) then set6(43,x)
every odd numbered set having 2 difference and even numbered sets having variable difference(12,12+8,..) a difference..so next set will have the difference of 12+8+8=28 so the value of x is 43+28=71.

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Balakumaran N.A   13 years AGO

lets take negative seq.
-7, (-7+-14) -21, (-21+-22)-43,... in the same way its increasing by 14,22,30,etc...so, positive seq.

5, (5+14)19, (19+22)41, (41+30)71, etc ...

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ULAGUNATHAN   13 years AGO

the difference between them is 2,12,2,20,2,28,2...
so the next term is 71

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KALPANA G   13 years AGO

2^2 +1=5, 2^2 +3=7,
4^2 +3=19, 4^2 +5=21,
6^2 +5=41, 6^2 +7=43,
8^2 +7=71, 8^2 +9=73

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