A builder is tiling a bathroom using black and white tiles. For every 3 black tiles, he uses 7 white tiles as shown. He uses 56 white tiles. How many black tiles does he use?

Answer 1

Let the number of black tiles used be B and the number of white tiles used be W.

Given that for every 3 black tiles, 7 white tiles are used, we can write the equation:

7/3 = W/B

Substitute the known values:

7/3 = 56/B

Multiply both sides by 3:

7 = 168/B

Divide both sides by 7:

B = 24

The builder uses 24 black tiles.