Statement: Some days are nights. Some nights are weeks. Some weeks are months. All months are years. Conclusions: I. Some years are nights. II. Some years are days. III. Some months are nights. IV. Some years are weeks.

Some nights are weeks + All weeks are months = I + A = I = Some nights are month → conversion → Some months are nights (I) Hence III follows. = Some nights are month + All months are years = I + A = I Some nights are year → conversion → Some years are nights (I) Hence I follows. All weeks are months + All months are years = A + A = A = All weeks are years → conversion → Some years are weeks (I) Hence IV follows. Some days are nights + Some nights are years = I + I = No conclusion Hence II does not follow.