A sequence is given by 1, 3, 6, 10, 15, ?. What is the next number?
Q1. A sequence is given by 1, 3, 6, 10, 15, ?. What is the next number?
Answer: 21
Explanation: The sequence is formed by adding 2, 3, 4, 5, 6, ... to the previous term, so the next number is 15 + 6 = 21.