Based on the number of apartments that Sasha can rent at 6 and 7 hours, her marginal benefit in the 7th hour is 3 apartments.
This refers to the additional number of benefits that Sasha gets when she works an extra hour.
As a result of working one extra hour from 6 hours to make it 7 hours, the additional benefit Sasha gets is:
= 12 - 9
= 3 apartments.
Find out more on marginal benefits at https://brainly.com/question/11937697.