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

### Instruction:
Dan's skateboarding helmet has ten more craters than Daniel's ski helmet. Rin's snorkel helmet has 15 more craters than Dan's and Daniel's helmets combined. If Rin's helmet has 75 craters, how many craters are in Dan's helmet?

### Response:
If Rin's snorkel helmet has 75 craters, then Dan's and Daniel's helmets combined have 75-15 = <<75-15=60>>60 craters.
Let's assume Dan's helmet has C craters.
Since Dan's skateboarding helmet has ten more craters than Daniel's ski helmet, the total number of craters their helmets have is C+(c-10)
For the total number of craters to be 60, the following equation should be satisfied: C+(c-10)=60
This translates to C+C=70
2C=70
The total number of craters that Dan's helmet has is C=70/2
Dan's helmet has 35 craters.
#### 35