Step-by-step explanation:
Initially, Gineva had 8 beads that were each 3 centimetrs long, so the total length of her necklace was 8 * 3 = 24 centimetrs.
Halfway through, she loses 2 beads, so the number of beads she has left is 8 - 2 = 6 beads.
The length of the necklace now is 6 * 3 = 18 centimetrs.