Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 吉娜因为只给了5%的小费而被认为是个小气的人。如果好的顾客至少给20%的小费，吉娜在一张26美元的账单上要给多出多少分才能被认为是个好的顾客？


### Response:
 她通常会给的小费金额是26美元 x 5% = $<<26*0.05=1.3>>1.3
要被认为是个好的顾客，她必须给的小费金额是26美元 x 20% = $<<26*0.2=5.2>>5.2
两者之间的差额是5.2 - 1.3 = $<<5.2-1.3=3.9>>3.9