What is 4 2/10 - 2 8/10

An unknown number of kids and buses are getting assigned. when assigning 4 kids to each bus, there are 2 kids that aren't placed in a bus. when assigning 8 kids to each bus, there are 2 empty buses. how many total kids are there?

What is the solution to the equation 9^(x+1) =27

He concluded that a heavier object dropped from the same height as a lighter object will land