If the temperature of the egg is x, then if x is below 23 (x<23), they rarely hatch. If x is greater than 33 (x>33), they also rarely hatch. For them to not rarely hatch, then x must be not below 23 (greater than or equal to) and not above 33 (less than or equal to), resulting in our compound equality being
23≤x≤33 and our pair of simple inequalities being x≥23 and x≤33.
