Two enterprising college students decide to start abusiness. They will make up and deliver helium bal-loon bouquets for special occasions. It will cost them$39.99 to buy a machine to fill the balloons withhelium. They estimate that it will cost them $2.00 tobuy the balloons, helium, and ribbons needed to makeeach balloon bouquet. Which of the following expres-sions could be used to model the total cost for produc-ing bballoon bouquets?

单项选择题A bag contains 6red marbles, 5yellow marbles, and 7green marbles. How many additional red marblesmust be added to the 18marbles already in the bag sothat the probability of randomly drawing a red marble is 3 5?

单项选择题The slope of the line with equation y=ax+b is greater than the slope of the line with equation y=cx+b.Which of the following statements mustbe true about the relationship between a and c?A.a≤cB.acE.a≥c+1

单项选择题In teaching a lesson on the concept of thirds, Ms. Chu uses a divide-and-set-aside procedure. She starts with acertain number of colored disks, divides them into 3equal groups, and sets 1group aside to illustrate 1 3.She repeats the procedure by taking the disks she hadNOT set aside, dividing them into 3equal groups, andsetting 1of these groups aside. If Ms. Chu wants to beable to complete the divide-and-set-aside procedure at least 4times (without breaking any of the disks intopieces), which of the following is the minimumnumber of colored disks she can start with?

单项选择题In Trial 9, the electrical force exerted by Sphere Y on Sphere X and the electrical force exerted by Sphere X on Sphere Y were exerted in which direction(s)?

单项选择题If Trial 4 had been extended, at approximately what time would 0.45 mL of 0 2 have reacted?

单项选择题One of the cornfields involved in the studies had an area of 2.5 hectares. In Study 2, how many kg N was added to that field as fertilizer N ?

单项选择题Based on the description of a lahar deposit, how do clasts and matrix particles differ in size?

单项选择题According to Figure 3, clasts and matrix particles having diameters greater than or equal to 0.5 mm made up approximately what percent of the total mass of the combined samples?

单项选择题Tomas plans to construct a circular fishpond with a diameter of 9 ft. Which of the following is closest to the length, in feet, of the decorative fencing that Tomas needs to enclose the fishpond along its perimeter?

单项选择题Christopher bought 4 cans of soup for a total of $3.36,which included sales tax of $0.16. At the same per-can cost, what is the cost before the sales tax is added for 6 cans of the same soup?