Note 1 at Jn. 20:1: John records Mary Magdalene as coming to the tomb in a manner that would make us think she was alone. Yet Matthew and Mark mention Mary Magdalene by name as being with the other women at the tomb.

One possible explanation of this is that the women were meeting at the tomb and Mary Magdalene arrived before the others. She then could have run to tell the apostles what had happened while the other women who are mentioned were still arriving. They would have entered into the empty tomb to see for themselves while Mary Magdalene was in transit.

It would then have been these other women who saw the two angels that Luke records in Luke 24:4-7. Close to the time that these other women leave the tomb to go back and tell the others, Mary Magdalene arrives back at the tomb with Peter and John (Jn. 20:3-10). Then as Mary Magdalene lingers in the area of the tomb, she is the first one to whom the resurrected Jesus appears (Mk. 16:9; Jn. 20:11-18).

Later, as the other women are going back to tell the apostles of what they have seen, Jesus appears to them also (Mt. 28:9-10).

With these events being so intertwined and the time frame being only a matter of minutes, it certainly would not be incorrect for Matthew, Mark, and Luke, who did not go into as much detail as John, to include Mary Magdalene in the group of women at the tomb. John's account simply adds more detail, and is not a contradiction.