What will come in place of the question mark (?) in the following number series? 4, 11, 21, 34, ? MCQ with Answer and Explanation

Explanation:
The differences between consecutive terms are: 3-1=2, 6-3=3, 10-6=4, 15-10=5. The differences are increasing by 1 each time. The next difference should be 6. Therefore, the next term is 15+6=21.[reference:1]

Explanation:
The series consists of squares of odd numbers: 3², 5², 7², 9². The next term is 11²=121.

Explanation:
The differences are: 5, 7, 9, 11. These are consecutive odd numbers. The next difference is 13. Therefore, 40+13=53.