What is BCR?
Benefit-Cost to Ratio, or BCR, is calculated by dividing the benefits by the costs. If the ratio is greater than or equal to 1.0, the benefits exceed the costs and the project is cost-effective. If the ratio is less than 1.0, the costs exceed the benefits and the project is not cost-effective.

What percentage is needed to pass the PMP exam?
61%

What is PERT?
The standard deviation term refers to how you determine your optimistic, most likely, and pessimistic times. If you have lots of historical data, you can plot and calculate the times using the mean, deviation, and other statistical methods. If you don't (which is where most people are), you rely on experts / industry benchmarks, etc. or you determine it based on a group technique.