Question

(01.02) Danica is arranging flowers for a party. On each table, t, there will be a vase of 9 flowers and 3 bowls of flowers with f flowers inside. Danica needs an additional 12 flowers for a cake topper. This situation can be written as the following expression: 9t + (3f)t + 12 How many flowers should Danica purchase if she has 21 tables with 3 flowers in each bowl?

Answer 1

Well, we can substitute the variables and get : 
9(21)+3(3)(21)+12
Then we simplify :
189+189+12
To get :
390 flowers

By the way you might be confused like I was for it said "a cake topping," whilst I assumed all tables had cake toppings which is untrue and I nearly ended up with 630 flowers.