brainlist asap !!
___________

1) find the simple interest: ____
principal: $6000
interest rate: 5%
time: 6 months

_____________
2) find the interest rate: ____
principal: $500
interest: $60
time: 3 years

_____________

3) find the principal amount: ____
interest rate: 4%
interest: $784
time: 20 years

also if you guys have the time can you please explain how to do problems like these it'll mean alot !!