Is the Calculation of 4 Fringes Correct Instead of 5?

[Miike012]

Question are in paint doc. My answer is in red... I believe the answer is 4 and not 5. Please someone let me know if I'm correct.

 

[mfb]

The single-slit minimum cannot be at the 5th fringe on one side, as this has to be bright. The minimum has to be between 5 and 6, so the second minimum is somewhere between 10 and 12 (not inclusive). This gives 5 or 6 as possible answers.