For a party you can spend no more than $20 on cakes. Egg cake costs $4 and cream cake costs $2. Write the linear inequality that models this situation

Question

I know one of the inequalities is 4e+2c is less than or equal to 20

Answer 1

You have answered your own question: 4e+2c≤20 says the total cost of egg cake is 4e dollars and the total cost of cream cake is 2c dollars, and the sum must not exceed $20, must be less than or equal to $20.

The equation can be divided by 2: 2e+c≤10 or c≤10-2e. This shows clearly the relation between c and e. If, for example, e=3 then c≤4.

Answer 2

.Ten years now, A will be twice as old as B. Five years ago, A was three times as old as B. What are the present ages of A and B?