Answer: Mrs, William takes 18 treats to school.
Step-by-step explanation:
Given: When the crispy treats have cooled Mrs. Williams cut theme into 30 equal pieces .
She give 2/5 to her son, then the number of treats ahe give to her son = [tex]\frac{2}{5}30=12[/tex]
Then, the number of treats Mrs. Williams take to school =[tex]30-12=18[/tex]
Hence, Mrs, William takes 18 treats to school.