Answer: 54 green beads
Explanation:
From the question, we are informed that Lucia is making a 21.6 centimeter beaded string to hang in the window and that she decides to put a green bead every 0.4 centimeters and a purple bead every 0.6 centimeters.
The number of green beads that she will need will be gotten by dividing the total length of bead she wants to make by 0.4. This will be:
= 21.6 / 0.4
= 54 green beads