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

### Instruction:
Keith and Blaine went fishing. Blaine caught 5 fish while Keith caught twice as many as Blaine's. How many fish did they catch together?

### Response:
The number of fish caught by Keith is 5 x 2 = <<5*2=10>>10.
Therefore, the total number of fish they caught is 10 + 5 = <<10+5=15>>15.
#### 15