A 0.500-kg block of iron at 60.0C is placed in contact with a 0.500-kg block of iron

Question:

A 0.500-kg block of iron at 60.0°C is placed in contact with a 0.500-kg block of iron at 20.0°C.
(a) The blocks soon come to a common temperature of 40.0°C. Estimate the entropy change of the universe when this occurs.
(b) Estimate the entropy change of the universe if, instead, the temperature of the hotter block increased to 80.0°C while the temperature of the colder block decreased to 0.0°C.