Item: tVerbalRuleExplicitModelGeometric2a
Stem:
Katie is a biochemist. During her last trip to the Amazon
rainforest, she brought back some leaves from a plant.
The substance she extracted from the leaves has some
amazing properties. One drop of the substance on a given cell causes it to grow and divide,
so that it generates an additional cell of the same size, along with a smaller bonus cell.
Immediately after the first division, there are three cells (2 large and 1 small).
During the next division, the number of large and small cells doubles again, for a total
of 6 cells (4 large ones and 2 small ones). The same pattern continues for each new division.
Your task is to find the total number of cells present
as a result of the third division.
Options:
3
6
12
24
Key:
- Observable: 3.
Score: 1;
Evidence Value: 1.
-
Student:Correct, good job!
-
Teacher:The student sucessfully modeled a real world problem using a simple geometric sequence.
- Observable: 1.
Score: 0;
Evidence Value: 0.
-
Student:Sorry, that's not right. You found the number of cells present as a
result of the first division (3). At the second division, there would be 6 cells, and at the third
division, there would be a total of 12 cells, which is the correct answer.
-
Teacher:Looks like the student computed the number of cells present as a result of the first division.
- Observable: 2.
Score: 0;
Evidence Value: 0.
-
Student:Sorry, that's not right. You found the number of cells present as a
result of the second division. Double that number to get 12, the number of cells present after
the third division.
-
Teacher:Looks like the student computed the number of cells present as a result of the second division.
- Observable: 4.
Score: 0;
Evidence Value: 0.
-
Student:Sorry, that's not right. You found the number of cells present as a
result of the fourth division. At the first division there are 3 cells, at the second
division, there are 6 cells, and at the third
division, there are a total of 12 cells, which is the correct answer.
-
Teacher:Looks like the student computed the number of cells present as a result of the fourth division.
Metadata:
Item Node: tVerbalRuleExplicitModelGeometric2a,
Difficulty: 2.
Proficiencies: VerbalRuleGeometric,
ExplicitGeometric,
ModelGeometric.