ICMS was having a spring dance. By Tuesday; 65 students had bought tickets for the dance. This 42% of the student body. How many students attend ICMS?

How to do this , and can some one explain

Can someone explain to me how to do

Aaron invested a total of $4,100, some in an account earning 8% simple interest, and the rest in an account earning 5% simple interest. how much did he invest in each account if after one year he earned $211 in interest? select one: a. $200 at 8%, $3,900 at 5% b. $3,200 at 8%, $900 at 5% c. $900 at 8%, $3,200 at 5% d. $3,900 at 8%, $200 at 5%