3, 15, 27, 39, ...

Describe the rule for the sequence.

Answer: The sequence is to add 12 to each new term.

Step-by-step explanation: The Best way to solve these type of questions is to quests and check. For example, one may notice 3 can be multiplied by 5 to get 15. However, 15 times 5 is 75, not 27, so the rule of multiply by 5 is not correct. Then, you may guess that the rule is to add some number to get the next. One may then notice that it is increasing by 12 each time.