The fare to the Boston University campus should be
You must have the Uber or Lyft app on your phone. Follow signs at the airport
for App Ride/TNC. This will take you to a parking lot where you can use the
app to call a ride. The fare to the BU campus should be around $20.
By subway: The airport is connected to Boston University via the subway (called the "T"). Boston University lies on the Green Line, sandwiched between the B line to the north and C line to the south. The easiest access to BU from the airport is via the B line.
At Logan, get on the Silver Line bus towards South Station. At South Station, get on the Red Line towards Alewife, you will transfer at Park Street.
At Park Street, go upstairs to the Green Line trolley platforms and take the "B" line towards Boston College.
The Department of Mathematics and Statistics is in the MCS building, one block south of the "BU East" stop on the Green Line on Cummington Street.