Fan and ! . the cost of coffee is determined by the type of coffee beans that are mixed together. the cost of a local mix of arabica and robusta beans is modeled by the equation below where a = the pounds of arabica and r = pounds of robusta.. 700a + 1200r = 1,000,000. if a mixture contains 1000 pounds of arabica beans, how many pounds of robusta beans should be in the mixture? . r = pounds

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?

Sasha drank 8 bottles of water everyday for a week. how many bottles of water did she drink in total?

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.