Mary took out a student loan for $15,000 at 4% simple interest. how much interest will she pay after 10 years

write in simple interest formula,
substitute the given values
and solve for the missing variable

Sandy is upgrading her internet service. fast internet charges $20 for installation and $52.45 per month. quick internet has free installation but charges $57.45 per month. part 1 out of 2 complete the equation that can be used to find the number of months after which the internet service would cost the same. use the variable x to represent the number of months of internet service purchased.