Seitokai tantei kirika manga

Seitokai Tantei Kirika summary:

Kirika Hijiribashi is the Executive Committee Treasurer managing a high school Student Council budget of 800 million yen. She is also the only committee member with an additional title: Student Council Detective able to sniff out amazing solutions to bizarre cases. Hikage Makimura, who recently transferred into the high school, finds himself not only tricked into joining the Student Council, but is now assigned as her assistant.