In ternary system, the number can only be 0, 1 or 2.

100 1 (binary) = 2 3+1= 9

10 1 1 (binary) = 2 3+2+1=1.

102 (ternary) = 3 2+2 =11

202 (ternary) = 2 * 3 2+2 = 20,

To sum up, we can get: b= 1, a= 1, and the decimal equivalent to two numbers is 1 1.