1, 45 yuan: the loan is 3,000 yuan, the loan days are 30 days, and the daily interest rate of Meituan's loan is 0.05%, so the monthly interest is 3,000 times 0.05% times 30, which is equal to 45 yuan.

2.54 yuan: If the loan is 3,000 yuan, the loan term is 90 days, and the daily interest rate of the loan is 0.02%, then the monthly interest rate of 3,000 times 0.02% times 90 is equal to 54 yuan.