On which day of the week did the women find that Jesus had risen?

Answer: The first day of the week

After the Sabbath, at dawn on the first day of the week, the women came to the tomb and the angel told them, "He has risen!"

“After the Sabbath, at dawn on the first day of the week, Mary Magdalene and the other Mary went to see the tomb. But the angel said to the women, “Do not be afraid, for I know that you are looking for Jesus, who was crucified. He is not here; He has risen, just as He said! Come, see the place where He lay.”— Matthew 28:1, 28:5-6 (BSB)