Sabrina used 21 tiles to make a design. She used twice as many blue tiles as red tiles. She used twice as many red tiles as green tiles. How many tiles of each color did Sabrina use?

Sabrina has 21 tiles overall.Green tiles: xRed tiles: 2xBlue tiles: 2 * 2x = 4xWe can write it all as:21 = x + 2x + 4x21 = 7x                              / ÷ 7 (both sides)x = 3Doublecheck:Green tiles: 3Red tiles: 2 * 3 = 6Blue tiles: 2 * 6 = 12All tiles: 3 + 6 + 12 = 21Correct :)