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

### Instruction:
 Carl is taking a class where the whole grade is based on four tests that are graded out of 100. He got an 80, a 75 and a 90 on his first three tests. If he wants an 85 average for the class, what is the minimum grade he needs to get on his last test?


### Response:
 Carl需要总共340分，因为85 x 4 = 340分
他已经得到了245分，因为80 + 75 + 90 = 245分
他需要在最后一次考试中得到95分，因为340 - 245 = 95分