Do the ratios 12:9 and 20:15 form a proportion?

Ihave trouble finding the nth term of a linear sequence

Select the margin of error that corresponds to the sample mean that corresponds to each population: a population mean of 25, a standard deviation of 2.5, and margin of error of 5%

Adesigner charges a one time fee of $200 plus $40 an hour for each project. write an expression to represent how much money the designer will make for a project