Ok, so i understand that DeltaT = Delta L /coff Lo But im not sure how to figure it with two different substances, Given: A brass plug is to be placed in a ring made of iron. At room temperature (20oC), the diameter of the plug is 8.759 cm and that of the inside of the ring is 8.741 cm. They must be brought to what common temperature (in Co) in order to fit? The coefficient of linear expansion for brass is 10x10-6(Co)-1 and that for iron is 12x10-6(Co)-1. Can someone please explain to me what i should be doing since there are two different materials?