RACHEL has two bowls of soup at 90'C with the same heat capacity of 2000J'C-1.SHE pours one of them into a cup at an ini

RACHEL has two bowls of soup at 90'C with the same heat capacity of 2000J'C-1.SHE pours one of them into a cup at an initial temperature of 25'C and leaves the other one on a table.the cup has a heat capacity of 200J'C-1.if the bowl of the soup on the table cools at average rate of 18W while the soup in the cup cools at an average rate of 3W,calculate their temperatures after 45 minutes.'
题目中2000j‘C-1 和 200J'C-1 中的-1，意思是 负一次方。