In the classroom, everyone shook hands with every other student. If the total numbers of students hands' shook is 528, how many students are in the class?

22. catie is starting a babysitting business. she spent $26 to make signs to advertise. she charges an initial fee of $5 and then $3 for each hour of service. write and solve an inequality to find the number of hours she will have to babysit to make a profit. interpret the solution.!