Question

What is the sum of 8th and 9th term of following series: 2, 3, 5, 7, 11, 13, 17, ...

Answer 1

As this series is constituted of consecutive prime no. So the 8th nd 9th term would be 19 & 23 respectively. So the sum of those no. Is 19+23=42.

Answer 2

13+17-11=19
19+17-13=23
Sum=19+23=42