Answer:
To simply let us denote the entities involved as follows;
Let,
Ladies be called as L
Girls be called as G
Boat be called as B
Let W be the west coast where everyone is currently present and
E be the east coast where everyone should be at the end.
Step 1:
Let the 2 girls cross from W to E
W [L,L]
E[G,G,B]
Step 2:
Let G return with the boat
W [L,L,G,B]
E[G]
Step 3:
Let L go with B
W [L,G]
E[L,G,B]
Step 4:
Let G return with the boat
W [L,G,G,B]
E[L]
Step 5:
Let the 2 girls cross from W to E
W [L]
E[L,G,G,B]
Step 6:
Let G return with the boat
W [L,G,B]
E[L,G]
Step7:
Let L go with B
W [G]
E[L,L,G,B]
Step 8:
Let G return with the boat
W [G,G,B]
E[L,L]
Step 9:
Let the two girls go in the boat to E
W [empty]
E[L,L,G,G,B]