Are These Algebra 2 Answers Correct?

Question

1. The organism grew exponentially. At first, it had 1200 cells. After two days it had 3000. Which of the following comes closest to the number of cells it will have after five MORE days?

(A) 11,900

(B) 29,600

(C) 6,300

(D) 15,800

(E) 10,500

For this question I got; (B) 29,600. Is this the correct answer?

1. How many possible answer combinations are there to a nine question multiple choice test with five options per question?

(A) 1953125

(B) 59049

(C) 362880

(D) 45

(E) None of the above

The answer I got to this is; (A) 1953125. Would this be correct?

Answer 1

I agree with your answers. In the first case you set up the growth equation to be equal to the final value equals the initial value times e raised to the KT power, where T at this point is in days. So the first goal is to determine what decay is. So I set 3000 equals 1200 (e)^k2. Solving for K, I got K = .458. Now let's determine a final value (call it F) after seven days (five additional days to the first calculation of 2 days). Using the K from above, I got: F equals, 29,616.

For your second problem I took the number of permutations of five things taken one at a time, and I got 5. In fact in this case it doesn't matter if you take the number of combinations or permutations. Then you have this raised the ninth power for nine different questions with five optional answers. Five to the ninth is equal to 1,953,125. This is so big that for each of the nine questions only one of the five options can be chosen as the possible correct answer

Answer 2

To get from 1200 to 3000 after 2 days; 58.14% is used. After 5 more days=29670.