Multiple choice

Find the next term of the series. 12, 23, 35, 47, 511, 613, ?

  1. 715

  2. 719

  3. 717

  4. 721

  5. 720
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The terms combine consecutive integers with the corresponding prime numbers: 1 and 2 give 12, 2 and 3 give 23, 3 and 5 give 35, and so on. The next pair is 7 and 17, giving 717.

Keep practicing — related questions