This riddle has been around for some time on internet platforms such as Instagram, Facebook, and WhatsApp, and many people still argue over what the answer might be, as there are many possibilities. The correct answer is Immediately after the guard goes back to his post upon checking the bridge, you start to cross the bridge. Just before the 6 minutes is up, turn around and start walking back towards the guard. The guard will come out and notice you and assume that you are a visitor coming from the other side of the bridge. He will go back to his post since he will not turn you away until you reach him. Once the guard has gone back, immediately turn back around and walk to the other side of the bridge. Since you had walked almost 6 minutes previously, you will reach the other end of the bridge in about 4 minutes time – before the guard comes out of his post again.