Final answer:
The risk of an ovarian neoplasm being malignant is 10-15% in pre-menopausal women and 20-30% in post-menopausal women.
Step-by-step explanation:
The risk of an ovarian neoplasm being malignant differs between pre- and post-menopausal women. In pre-menopausal women, about 10-15% of ovarian neoplasms are malignant. On the other hand, in post-menopausal women, the risk increases to 20-30%.