APTITUDE | ARITHMATICAL | ODD MAN OUT AND SERIES | INSERT THE MISSING NUMBER 1

DIRECTIONS : Insert the missing number

1.	2, ..., 8, 16, 32, 64, 128, 256
	A.   6	B.   5
	C.   4	D.   3

Solution

4. Each number of series is the double of the preceding number. The missing number will be 4.

2.	17, 7, 24, 19, 9, 28, ..., 8, 31
	A.   20	B.   21
	C.   18	D.   23

Solution

23. Each 3rd number is the sum of preceding two numbers.i.e .,17+7=24, 19+9=28, 23+8=31. Hence the missing number will be 23.

3.	121, 112, ..., 97, 91, 86
	A.   102	B.   108
	C.   99	D.   104

Solution

104. Series is written in descending order with a difference of 9, 8 ,7, 6 and 5 respectively. Hence ,the missing number will be 104.

4.	6, 7, 9, 13, 21, ...
	A.   25	B.   29
	C.   37	D.   32

Solution

37. Series moves with a difference of 1, 2, 4, 8, 16. Hence the missing number will be 37. i.e., 6+1=7, 7+2=9, 9+4=13, 13+8=21, 21+16=37.

5.	2, 9, 28, 65, ...
	A.   126	B.   195
	C.   121	D.   103

Solution

126. Method used to from the series is :(1)³+1, (2)³+1,(3)³+1, (4)³+1 Therefore the missing number is (5)3 +1= 126.