Choose the number that comes next: 4, 7, 12, 19, 28, ?

36Correct answerYour answer37Correct answerYour answer38Correct answerYour answer39Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer D

Correct answer: D

Differences: 3, 5, 7, 9, rising by 2, so the next difference is 11.
Next term $= 28 + 11 = 39$ . Check: the terms are $1^2 + 3, 2^2 + 3, 3^2 + 3, 4^2 + 3, 5^2 + 3$ , and $6^2 + 3 = 39$ .

Worth noting

36 is $6^2$ without the +3. 37 repeats the last difference, 9, and 38 adds 10, as if the differences rose by 1.

Ten questions from Number and Letter Series, at your own pace.

Ten questions from Number and Letter Series, at your own pace.

Explanation