Respuesta :

21.1 Because 12.3-3.12 is that answer.
Hey there,

The first ribbon is 12.3 feet

The second is 3.12 feet shorter

12.3 - 3.12 = 9.18

The second ribbon is 9.18 feet

Now add the two:
12.3 + 9.18 = 21.48

The two ribbons are 21.48 feet

Hope I helped :)

~Char