Why do we not use closed parentheses/brackets for positive and negative infinity?

During your cycling trip, you and your friends often stayed in hostels. the prices of these are listed below. hostel standard room (price per night) with breakfast (price per night) super sleep hostels £22.45 £28.65 normandy nights £18.55 £25 zzzola hostels £24.50 £30.99 belgian beds £11.20 £18.55 night-time rest days ? £33 what is the range in cost for a single night, including both standard room prices and with breakfast prices?

Can someone me and plz do the problem

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?