Assume an MBS is composed of the following four different pools of mortgages:

• $2 million of mortgages that have a maturity of 90 days.
• $3 million of mortgages that have a maturity of 180 days.
• $5 million of mortgages that have a maturity of 270 days.
• $10 million of mortgages that have a maturity of 360 days.

What is the weighted average maturity (WAM) of these mortgage pools?