After the ovulation test strip shows a positive result, how long before it shows a strong positive?

Patient's question:

No

Doctor's answer:

Positive indicates ovulation in the next 24 to 48 hours. Online says that eggs survive for 12 to 24 hours after being released, and if they are not fertilized during this period, they will fail. If you want to have a child, you can have sex two days before ovulation and one day after ovulation.