A family quarantined at home in March/April 2020 has two dogs: a bull mastiff (Biggie), and a chihuahua (Smalls). Smalls has a bark with SPL of 80 dB. When the mail carrier comes to drop off the mail, both Biggie and Smalls bark and the SPL of their combined barks is 90 dB. What is the SPL of Biggie?