What is the next number in the sequence 1, 3, 6, 10, 15, 21, ...?
Answer and explanation
Correct answer: B.
- Step 1: The differences grow by one each time (+2,+3,+4,...) so the terms are triangular numbers.
- Step 2: The next term is .
Answer
.
Why not the others: , and do not fit.
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