Atiled area in a kitchen was made with a ratio of 7 black tiles for every 3 white tiles. if 80 tiles were used, how many tiles were black?

So the way i did it was by seeing that the 7 black and 3 white equaled 10 tiles. so i saw this and realized you would repeat this pattern 8 more tiles to get the 80. So you would take the 7*8 to get 56 black tiles and if you do the same for the white tiles you would get 24 white tiles. Add them together and you get 80. So there would be 56 total black tiles

B, 0.4 repeats so it is rational and square root of 16 is 4 so that is rational as well.