There was an event held by a group. In this COVID-19 era, there were many hardships in equipping quarantine supplies, in addition to carrying out the event. Several bottles of the same hand sanitizer were purchased for those attending the event. One bottle of the sanitizer for every ten people was equipped. One to ten people need a bottle of the sanitizer, but if they are eleven, two bottles are needed.
Initially, hand sanitizers were prepared according to the number of people scheduled to attend, but on the day of the event, exactly one-third of the scheduled participants were absent, so 12 bottles of the sanitizer did not need to be taken out of the warehouse.
At most, how many people were expected to attend this event?