To determine how much money Rosa has made or lost by the end of the second day, we need to calculate the total amount of money she received and compare it to the initial amount she had.
1. Initially, Rosa and her four friends shared $87, so each of them received $87 / 5 = $17.40.
2. On the first day, they made a total of $37. Since there were five of them, each person contributed $37 / 5 = $7.40.
3. After the first day, Rosa and two friends showed up on the second day. They made $19. Since there were only three of them, each person contributed $19 / 3 = $6.33.
4. Adding up the contributions from both days, Rosa has received $7.40 + $6.33 = $13.73.
5. Comparing this total to her initial share of $17.40, we can calculate the difference. Rosa has lost $17.40 - $13.73 = $3.67 by the end of the second day.
In summary, by the end of the second day, Rosa has lost $3.67.