Firecrackers 1 and 2 are 600 m apart. You are standing exactly halfway between them. Bob is standing 300 m on the other side of firecracker 1. You see the flashes of light from the two firecrackers exploding at the exact same instant.
a) Does Bob see both firecrackers explode at exactly the same time, firecracker 1 explode first, or firecracker 2 explode first? Explain.