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What should come in place of the question mark (?) in the given series?
79 88 100 115 133 154?
170
181
178
175
178
Observe the differences between consecutive terms; they follow a simple arithmetic progression: 9, 12, 15, 18, 21, 24.
Observe the differences between consecutive terms; they follow a simple arithmetic progression: 9, 12, 15, 18, 21, 24.
Calculate Differences
Calculate the difference between consecutive terms: 88-79=9, 100-88=12, 115-100=15, 133-115=18, 154-133=21.
Identify Pattern
The differences (9, 12, 15, 18, 21) form an arithmetic progression with a common difference of 3.
Determine Next Term
The next difference must be 21 + 3 = 24. Adding this to the last term, 154 + 24 = 178.
A: 170 is incorrect as it implies a difference of 16; B: 181 is incorrect as it implies a difference of 27; D: 175 is incorrect as it implies a difference of 21.
C is correct because the series follows a pattern of adding increasing multiples of 3 (9, 12, 15, 18, 21, 24) to each preceding number.
If the differences are not constant, always check the difference of the differences; it often reveals a simple constant increment like +3 in this case.