Mr. Gilbert threw a party for all his friends and relatives. He told them to arrive at 8 p.m. By 9 p.m. 1/3 of the invited guests had shown up. If he invited 36 guests, how many had shown up by 9 p.m.?
1/3 of 36 = 1/3 x 36 = $\boxed{12}$
+103 
