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17.

 Find out the wrong number in each sequence 4, 9, 19, 39, 79, 160, 319 (a)79 (b)160 (c)319 (d)19
Answer is: BDouble the number and add 1 to it, to get the next number. So, 160 is wrong

18.

 Find out the wrong number in each sequence 10, 14, 28, 32, 64, 68, 132 (a)32 (b)64 (c)68 (d)132
Answer is: DAlternately, we add 4 and double the next. So, 132 is wrong. It must be (68x2) = 136 Insert the missing numbers

19.

 Find out the missing number in sequence 4, -8, 16, -32, 64, â€¦.. (a)128 (b)-128 (c)132 (d)-132
Answer is: BEach numbers are multiple of -2. So, the required number is -128.

20.

 Find out the missing number in sequence 5, 10, 13, 26, 29, 58, 61, â€¦. (a)-122 (b)122 (c)-124 (d)124
Answer is: ANumbers are alternately multiplied by 2 and increased 3.
So, the missing number = 61x2 = 122

21.

 Find out the missing number in sequence 11, 13, 17, 19, 23, 29, â€¦ (a)30 (b)31 (c)32 (d)33
Answer is: BAll number are prime 31

22.

 Find out the missing number in sequence 16, 33, 65, 131, 261, â€¦. (a)520 (b)420 (c)523 (d)525
Answer is: CMultiply by two and add one.

23.

 Find out the missing number in sequence 3, 7, 6, 5, 9, 3, 12, 1, 15,â€¦. (a)-1 (b)-5 (c)25 (d)30
Answer is: AThere are two series, beginning respectively with 3 and 7. In one 3 is added and in another 2 is subtracted. The next number is 1-2 = -1

24.

 Find out the missing number in sequence 15, 31, 63, 127, 255, â€¦ (a)511 (b)540 (c)550 (d)560
Answer is: AMultiple by two and add one.