48 tiles for each of 8 rows. each row has 6 white tiles . the rest are purple. how many tiles are purple?

So this is saying that there are 8 rows, with 48 tiles in each row.  Each row has 6 white tiles, and the rest are purple.  That means each row has 42 purple tiles (48-6 = 42).

So you know that each row has 42 purple tiles, and there are 8 rows of tiles, so there are 42 x 8 purple tiles.

42 x 8 = 336