Brian can only hold his breath underwater for 10 seconds

Brian can only hold his breath underwater for 10 seconds. He wants to get better, so he starts practicing. After a week, he's doubled the amount of time he can do it. After another week, he's doubled it again from the previous week. The final week, he's increased it by 50% from the previous week. How long can Brian hold his breath for now?

GSM8K — Grade School Math 8K (Cobbe et al., OpenAI, 2021) · train #349