Good girls and bad boys (7)
On an island, there is this strange pattern - boys always lie while girls always tell the truth. This time round, you encounter four children.
The oldest one says, "Exactly one of us is a boy."
The second one says, "Exactly two of us are boys."
The third one says, "Exactly three of us are boys."
The youngest one says, "All four of us are boys."
Let 1 denote boys and 0 girls. In order of birth, identify the gender of each child and convert it into a number accordingly. Submit your answer as a string of 4 ones and/or zeroes. For example, if all four are boys, then your answer is 1111.