Consider the long division problem below. What error did Sam make when he computed the answer?

[tex]\[
\begin{array}{r}
-63 \\
0 . 0 4 3 \longdiv { - 0 . 2 7 0 9 } \\
-258 \\
129 \\
-129 \\
\hline
\end{array}
\][/tex]

A. The answer should be -6.3. Sam should have moved the decimal point 3 places to the right in both the divisor and the dividend.

B. The answer should be -630. Sam should have moved the decimal point 5 places to the right in both the divisor and the dividend.

C. The answer should be -65. Sam made an error subtracting 258 from 270.

D. The answer should be -61. Sam made an error when multiplying 6 times the divisor.



Answer :

Let's analyze the problem step-by-step to understand what Sam did and identify where the error occurred.

The problem is to divide [tex]\(-0.2709\)[/tex] by [tex]\(-0.043\)[/tex].

### Step 1: Correct placement of the decimal point
First, let's move the decimal point in both the divisor and the dividend to the right to eliminate the decimals.

- The divisor [tex]\(-0.043\)[/tex] becomes [tex]\(-43\)[/tex] after moving the decimal point [tex]\(3\)[/tex] places to the right.
- The dividend [tex]\(-0.2709\)[/tex] becomes [tex]\(-270.9\)[/tex] after moving the decimal point [tex]\(3\)[/tex] places to the right.

Now, the division problem is:
[tex]\[ -270.9 \div -43 \][/tex]

Since both the dividend and the divisor are negative, the result should be positive.

### Step 2: Perform the division

Let’s set up the long division:

[tex]\[ \begin{array}{r} -43 \\ -43 \longdiv { -270.9 } \\ \end{array} \][/tex]

#### First division:

- Determine how many times [tex]\(43\)[/tex] goes into [tex]\(270\)[/tex].
- [tex]\(43\)[/tex] goes into [tex]\(270\)[/tex] approximately [tex]\(6\)[/tex] times because [tex]\(43 \times 6 = 258\)[/tex].

#### Subtraction:

- Subtract [tex]\(258\)[/tex] from [tex]\(270\)[/tex] (similar to what Sam did):
[tex]\[ 270 - 258 = 12 \][/tex]

#### Next digit in the dividend:

- Bring down the next digit after the decimal point (if any). In this case, bring [tex]\(9\)[/tex] making the number [tex]\( 129 \)[/tex].

#### Second division:

- Determine how many times 43 goes into 129.
- [tex]\(43\)[/tex] goes into [tex]\(129\)[/tex] exactly [tex]\(3\)[/tex] times because [tex]\(43 \times 3 = 129\)[/tex].

#### Subtraction:

- Subtract [tex]\(129\)[/tex] from [tex]\(129\)[/tex]:
[tex]\[ 129 - 129 = 0 \][/tex]

So, the answer to the division is approximately [tex]\(6.3\)[/tex].

### Error Analysis

- The answer should be [tex]\( -65 \)[/tex]. Sam made an error subtracting [tex]\(258\)[/tex] from [tex]\(270\)[/tex].

Based on this correct division, noticing Sam's mistake confirms the precise error: Sam possibly miscalculated the results at the subtraction step.

The correct steps conclude that:
[tex]\[ \frac{-270.9}{-0.043} = 6.3 \][/tex]

### Conclusion:

The mistake Sam made was in the incorrect calculation during subtraction while doing the long division. Thus, the correct option is:
- The answer should be -65. Sam made an error subtracting 258 from 270.

Other Questions