Exotic series

Often some IPAT series cannot be classified in any one of the forms previously described. It is therefore important to gain adequate practice, recognize how the test thinks and link back to questions in the actual test.  Here are three sample questions known to have come in the IPAT to help get you started.

Q) 6, 24, 60, 120, ?

A] 210

B] 165

C] 240

D] 225

E] 250

Solution

Solution – A] 210.The series above is 1x2x3, 2x3x4, 3x4x5, 4x5x6. Hence the next term is 5x6x7 = 210

Q) 23456789,13456789,12456789,12356789,?

A] 23467981

B] 23467891

C] 12347689

D] 12346789

E] 12346780

Solution

Solution – D] 12346789. In the series above, each term has all the single digit numbers in it except the index number of its position in the series. For example 13456789, the 2nd term, has 2 missing in it. Hence the next number (5th) in the series will have 5 missing from it – 12346789

Q) 1/2,1/4,1/7, 2/11, 2/16, 2/22, 3/29, ?

A] 4/56

B] 5/124

C] 3/37

D] 9/82

E] 4/61

Solution

Solution – C] 3/37. The numerators follow a triplet matching rule – (1,1,1), (2,2,2)..

The denominators follow a increasing difference rule – 2(+2),4(+3),7(+4),11(+5),16(+6),22(+7),29

Hence the next term in the series is 3/(29+8) = 3/37

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