(B)Riley's class total times the amount of the cost price.
21 x [.35 .42]
Pemda -
"Please Excuse My Dear Aunt Sally". It stands for "Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction"
So we have Parentheses first. so add .35 and .42 (Make sure not to forget the decimals!!!!!!)
21 x .97
The total of .35 and .42 makes .97
Then multiply them both
21 x .97 =20.37
Landing you with the total 20.37
