Precalculus (10th Edition)

a)$0.25$ b)$0.55$
We know that probability$=\frac{\text{number of favourable outcomes}}{\text{number of all outcomes}}.$ There are $8+5+4+3=20$ bottles in total. a) $5$ are bottles of Coke, hence the probability: $\frac{5}{20}=0.25$ b) $8+3=11$ are bottles of Pepsi or IBC, hence the probability: $\frac{11}{20}=0.55$