The chromatogram below shows the separation of components in an over-the-counter pain reliever.

1: acetaminophen, tr 3.97 min, w1/2 0.12 min 2: caffeine, tr 6.15 min, w1/2 0.21 min 3: benzoic acid, tr 9.73 min, w1/2 0.35 min 4: aspirin, tr 14.8 min, w1/2 0.73 min

calculate the resolution r between acetaminophen and caffeine.

calculate the number of theoretical plates n for the peaks of acetaminophen and caffeine