288 tiles.
1.)Convert the feet to inches (24 in and 48 in)
2.) find the area of the the back splash using l*w (24*48=1152)
3.)Find the area of the tiles (2*2=4)
4.)Divide the area of the back splash by the area of the tiles (1152/4= 288)
Ps. I'm not the smartest human being in the world and i'm sorry if i'm wrong :)