Page 7 - Services Selection Board (SSB) Interviews

Number Series Completion 3
Pattern 7: Product of the digits and summation with any constant, gives next number of the series.
Ex 11: 69, 55, 26, 13, 5 [Find the Wrong term of the Series]
(a) 69 (b) 55 (c) 26
(d) 13 (e) 5

Solution: We found that the series contains each term is one more than the product of the digits of the preceding term.
Thus (6 × 9 ) + 1 = 55, (5 × 5) + 1 = 26, (2 × 6 ) + 1 = 13, (1 × 3) + 1 = 4. Hence option (e).

Pattern 8: Difference Between the adjacent numbers increases by a constant number.
Ex 12: 2, 7, 17, 32, ..?…….
(a) 42 (b) 52 (c) 47
(d) 27 (e) 62

Solution: In this particular series the gap between the numbers are 5, 10, 15, ...so the next difference must be 20.
Than the next number be 52. Hence option (b)

Pattern 9: Percentage increasing and decreasing pattern
Ex 13: 105, 94.5, 103.95, 93.56, ..?...
(a) 102.91 (b) 102.98 (c) 102.95
(d) 103. 91 (e) none of these
Solution: In this particular Series the numbers are arranged on percentage increase and decrease pattern. As first there
is 10% decrease and than 10% increase..i.e 105 – 10% of 105 = 94.5, 94.5 + 10% of 94.5 = 103.95 ..and so on.
Hence option (a) 102.91 is the very next number of the series.
Pattern 10: Division or Multiplication with increasing and decreasing numbers.
Ex 14: 51975, 9450, 2100, 600, 240, 160 ?
(a) 80 (b) 120 (c) 320
(d) 240 (e) 300

Solution: The pattern is
? = 160 0.5 = 320. Hence Option (c)

Ex 15: 16, 12, 18, 40.5, 121.5, 455.625 ?
(a) 2050.1125 (b) 2050.2125 (c) 2050.3125
(d) 2050.4125 (e) 2050.5125

Solution: The pattern of the above Series:
16 × 0.75 = 12, 12 × 1.5 (i.e 0.75 + 0.75 = 1.5) = 18, 18 × 2.25 (i.e 1.5 + 0.75 = 2.25) = 40.5, 40.5 × 3 (i.e 2.25
+ 0.75) = 121.5, ......, 455.625 × 4.50 = 2050.3125. Option (c)
Ex 16: 4,18, 48, 100, 180, 294 ?
(a) 448 (b) 424 (c) 436
(d) 460 (e) 412

Solution: The pattern is, here 3rd order difference is constant.

? = 294 + 154 = 448