Answer:
There is a 90.32% probability that the cake was baked by Doug.
Step-by-step explanation:
We have these following probabilities:
A 70% probability that Doug bakes the cake.
A 30% probability that Jeremy bakes the cake.
A 40% probability that a cake baked by Doug gets a thumbs up.
A 10% that a cake baked by Jeremy gets a thumbs up.
One cake was selected at random on 10/01/2014 and got a "thumbs up".
1. Find the probability that the cake was baked by Doug.
The probability that a baked cake gets a thumbs up is:
Of those, 0.7*0.4 = 0.28 are baked by Doug.
So the probability is:
There is a 90.32% probability that the cake was baked by Doug.