Well, to tile along the floor we will use the 6" ones Two 6 inch ones will make a foot. You want to tile 10'. so that must be 2*10 tiles. = 20 tiles along the floor
Now going up the wall. Each tile is 24" which is 2' 2' for one tile means 10/2 = 5 tiles to the ceiling.
So you have 20 across the wall and 5 up the wall. How many will that be? Use some paper and draw it if you need to.