Maggie has 20 ribbons. Of them, 2/5 ribbons are polka dotted ribbons. How many ribbons are not polka dotted

X = the number of polka dotted ribbons

X/20 = 2/5; using cross product find x

5x=20 (2)

5x=40

5x/5=40/5

X=8 there are 8 polka dotted ribbons

So you minus 8 for 20 to find the number of left over ribbons that are not polka dotted

20-8=12

12. 2/5 of 20 is 8 that ARE polka dotted, therefore there are 12 that are not.