Interest & late fees in GSTR-3B

Mam, If ITC is Rs 150. And Output tax is Rs 100. There is a delay of 2 days in filing GSTR-3B. Query-

a) Whether interest should be paid due to delayed filing of 3B ?

b) what is the late fees to be paid??

 2) If Input IGST is Rs 150. And Input CGST & SGST is Rs 50 each. Output CGST & SGST is Rs 200 each. So, net SGST payable is Rs 150. If there is delay of 2 days in filing GSTR-3B , then whether only SGST interest @ 18% should be paid ??

Thanks..