Since there are equal numbers of pieces, the chances of Julio getting a red on the first pull is 12/24 or 1/2 (reduced)
However on the second pull there are only 11 reds (Julio pulled one out) out of 23 remaining pieces so the chances of pulling the second red are 11/23
Now multiply those possibilities:
1/2 x 11/23 and you will get 11/46 which is the probability of pulling two reds in a row. 11/46 is the answer.