NIMCET 2022 — Reasoning PYQ

Step 1: Calculate the differences between consecutive terms

• First difference: (−5)−30=−35

• Second difference: (−45)−(−5)=−40

• Third difference: (−90)−(−45)=−45

• Fourth difference: (−145)−(−90)=−55

• Fifth difference: (−195)−(−145)=−50

• Sixth difference: (−255)−(−195)=−60

Step 2: Analyze the pattern of differences

The differences observed are:

−35,−40,−45,−55,−50,−60

A clear logical pattern is emerging where each subsequent difference decreases by an additional 5 (i.e., −35,−40,−45,−50,−55,−60).

Step 3: Identify the discrepancy

If the pattern were consistent (dn=dn−1−5):

• The difference after −45 should be −50.

• The term after −90 should be: −90+(−50)=−140.

• The term after −140 (with a difference of −55) would be: −140+(−55)=−195.

Since the sequence in the question uses −145 instead of −140, it breaks the pattern of both the current difference and the subsequent difference.

Corrected Series Comparison:

• Actual: 30→−35−5→−40−45→−45−90→−55−145→−50−195→−60−255

• Pattern: 30→−35−5→−40−45→−45−90→−50−140→−55−195→−60−255

Conclusion

The number -145 is wrong because it should have been -140 to maintain the constant decreasing interval of 5 in the differences.

Correct Option: (A) -145