Question

George evaluates the expression on a trivia quiz.
-8.13/2 1/10+12

He gets an answer of 8.88. Is this a reasonable answer?
A.
Since -8.13 rounds to -8 and rounds to 2, the final answer rounds to 8.
His answer of 8.88 rounds to 9. So, it is not reasonable.

B.
Since -8.13 rounds to -8 and rounds to 2, the final answer rounds to 9.
His answer of 8.88 rounds to 8. So, it is not reasonable.

C.
Since -8.13 rounds to -9 and rounds to 3, the final answer rounds to 10.
His answer of 8.88 rounds to 9. So, it is not reasonable.

D.
Since -8.13 rounds to -9 and rounds to 3, the final answer rounds to 9.
His answer of 8.88 rounds to 9. So, it is reasonable.

Answer 1

To evaluate George's answer, we first need to compute the expression:

\[
-8.13 / 2.1 + 12
\]

Calculating \(-8.13 / 2.1\):

\[
-8.13 \div 2.1 \approx -3.867619
\]

Now, adding \(12\):

\[
-3.867619 + 12 \approx 8.13238
\]

Thus, the final answer is approximately \(8.13\).

Now, let's analyze the rounding options:

1. Rounding \(-8.13\) gives us \(-8\).
2. Rounding \(2.1\) gives us \(2\).

So when calculating using the rounded values:

\[
-8 / 2 + 12 = -4 + 12 = 8
\]

Next, let's compare the final answers based on rounding:

- The calculated answer \(8.13\) rounds to \(8\).
- George's answer \(8.88\) rounds to \(9\).

Now let's evaluate the provided options:

- A: His answer of 8.88 rounds to 9. So, it is not reasonable. → This statement is **correct**.
- B: His answer of 8.88 rounds to 8. So, it is not reasonable. → This statement is incorrect.
- C: His answer of 8.88 rounds to 9. So, it is not reasonable. → This statement is **correct** but the reasoning is wrong since the final considers rounding to 8.
- D: His answer of 8.88 rounds to 9. So, it is reasonable. → This statement is incorrect.

Thus, the conclusion correct and reasonable should be option **A**, because the rounded value of the final answer is \(8\), while George’s answer of \(8.88\) rounds to \(9\), which is not reasonable.