The question states, "a chicken and a half", not "one and a half chickens". C+½ is not the same as 1½C (unless C=1).
I am not sure how "a half" can lay anything, nor how anything can lay "a half". The word, "half" is not normally used on its own although there are exceptions, for example, when referring to a half-pint of ale.
I am not sure how "a day and a half" should (if taken literally) be interpreted either. "Half-past" (in the UK) means "half an hour past" so does "a day and a half" mean 24½ hours?
If we assume that halves cannot lay eggs, the original question can be reduced to,
"If a chicken can lay an egg in a day, how many eggs can six chickens lay in a week?"
If we also assume that a chicken can lay an egg every day (or every 24½ hours, assuming that we are considering what a chicken
can lay in a week, not what it would do on average), one chicken can lay seven eggs in a week. Six chickens can, therefore, lay 42 eggs in a week.
XFool wrote:...Can "chickens" lay eggs?
That is irrelevant as the question was, "If...". The question would still be valid if it was, "If a cow and a half can lay an egg and a half in a day and a half, how many eggs can six cows lay in a week?".
Julian F. G. W.