Find the next number in the series: 78, 65, 82, 69, 86?

Correct option is D

Ans. (D)
Sol. Let's observe the pattern in the series:
· 78 → 65 (decrease by 13)
· 65 → 82 (increase by 17)
· 82 → 69 (decrease by 13)
· 69 → 86 (increase by 17)
The pattern alternates between decreasing by 13 and increasing by 17.
So, after 86, we should decrease by 13:
· 86 - 13 = 73