Problem 10. (4 points)

To buy new headphones costing 275 rubles, Katya decided to save money on sports activities. Until now, she has been buying a single-visit ticket to the swimming pool, including a visit to the sauna for 250 rubles, to warm up. However, summer has arrived, and the need to visit the sauna has disappeared. Visiting only the swimming pool costs 200 rubles more than visiting the sauna. How many times does Katya need to visit the swimming pool without the sauna to save enough to buy the headphones? (Provide the answer as a whole number, without spaces or units of measurement.)

Answer: 11.

## Comment:
Solution: one visit to the sauna costs 25 rubles, the price of one visit to the swimming pool is 225 rubles. Katya needs to visit the swimming pool 11 times without going to the sauna in order to save up for buying headphones.