Use the BERT analysis approach to calculate the project duration for the following project descriptions?

Greenfield Elementary School is initiating a project to develop a new School Management System $($SMS$)$ to streamline administrative tasks such as student enrolment, attendance tracking, and grade management. The project involves several key activities, each with varying durations due to uncertainties in development and testing.

Activities and Duration Estimates:

The project team has identified the following activities along with their optimistic, most likely, and pessimistic time estimates $($in days$)$:

Requirements Gathering

Optimistic: $3$ days

Most Likely: $5$ days

Pessimistic: $7$ days

System Design

Optimistic: $4$ days

Most Likely: $6$ days

Pessimistic: $10$ days

Development

Optimistic: $10$ days

Most Likely: $15$ days

Pessimistic: $20$ days

Testing

Optimistic: $5$ days

Most Likely: $8$ days

Pessimistic: $12$ days

Deployment

Optimistic: $2$ days

Most Likely: $4$ days

Pessimistic: $6$ days