Find out the wrong number in the FOLLOWING series.30, −5, −45, −90, −145, −195, −255
The series is: 30, -5, -45, -90, -145, -195, -255
Differences between consecutive terms:
The differences should decrease by 5 each time: -35, -40, -45, -50, -55, -60. However, the fourth difference is -55 instead of -50, indicating an error. The term after -90 should be -90 + (-50) = -140, but it is given as -145. Thus, -145 is the wrong number.
Answer: (A) -145
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