If each room mates bank account loses $810.50 after paying rent, it means they are spending that on rent. Since there are 4 friends, just do $810.50 times 4 and that's the answer of how much rent costs in total.
there were three times as many new subscribers in the 20-29 and the 30-39 age groups combined for the chronicle than in the 20-29 age group for the times.
