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

### Instruction:
On Miss Lawrence's math exam, 80% of the 50 questions are problem-solving while the rest are multiple-choice questions. How many multiple-choice questions are there?

### Response:
80% of the questions are problem-solving, so the rest are multiple-choice.
100% - 80% = <<100%-80%=20%>>20%
20% of 50 questions = <<20%*50=10>>10
#### 10

