Answer:
34.5% probability that the jury returns a guilty verdict
Step-by-step explanation:
We have these following probabilities:
The defense attorneys have a 70% chance of convincing the jury that the police either contaminated or planted some of the key evidence.
In this case, there is a 15% probability that the jury will return a guilty verdict.
There is also a 100 - 70 = 30% of not convincing the jury that the police either contaminated or planted some of the key evidence.
In this case, 80% probability of the jury returning a guilty verdict.
What is the probability that the jury returns a guilty verdict?
15% of 70% and 80% of 30%. So
34.5% probability that the jury returns a guilty verdict