Question

Two blue armies are each poised on opposite hills preparing to attack a single red army in the valley. The red army can defeat either of the blue armies separately but will fail to defeat both blue armies if they attack simultaneously. The blue armies communicate via an unreliable communications system (a foot soldier). The commander with one of the blue armies would like to attack at noon. His problem is this: If he sends a message to the other blue army, ordering the attack, he cannot be sure it will get through. He could ask for acknowledgement, but that might not get through. Is there a protocol that the two blue armies can use to avoid defeat?

Answer 1

Yes there is...

Step-by-step explanation:

Since the Red army can defeat both blue army simultaneously, one part of the blue army should proceed with the attack at noon thereby sending the message to the other blue army using the confrontation or attack as the signal. Possibly while the confrontation will be on, the other blue army will join force.

Answer 2

I would attack with one blue army and while all the chaos I would send the foot soldier to the second blue army and tell them to attack with the first. Idk like if the foot soldier is the only way of communication, so yeah