What should come in place of the ‘?’ in the given series? 15 22 40 67 105 152 ?

First, look at the differences between consecutive terms: 22 - 15 = 7 40 - 22 = 18 67 - 40 = 27 105 - 67 = 38 152 - 105 = 47 Now, analyze the second-level differences (the differences between the consecutive differences): 18 - 7 = +11 27 - 18 = +9 38 - 27 = +11 47 - 38 = +9 Pattern Logic: The second-level difference follows an alternating pattern of +11, +9, +11, +9 Following this logic, the next difference to add to 47 is +11 {Next 1st Difference} = 47 + 11 = 58 Now, add 58 to the last term of the series (152): 152 + 58 = 210