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Mariah earns $32.75 per week working as a pet sitter. She worked as a pet sitter for 2 weeks. She previously saved $70.99 in allowance money. She spent $12.25 of her total earning to buy video games. Mariah put 1 over 4 of the remaining money in her savings account. Mariah used the following steps to find the total money she put in her savings account:

Step 1: [($32.75 ⋅ 2) + $70.99 − $12.25] ⋅ 1 over 4

Step 2: [$65.5 + $70.99 − $12.25] ⋅ 1 over 4

Step 3: $136.49 − $3.0625 = $133.4275

In which step did Mariah first make an error? Explain, using words, how Mariah can correct her error.

1 Answer

5 votes

Answer:

1) Step 3: S = $136.49 - $3.0625 × 1/4

2) By completing the operations within the parenthesis in Step 2, before multiplying the result by 1/4

Explanation:

1) From the given information, we have;

The amount amount Maria earns as a pet sitter = $32.75

The number of weeks Maria worked as a pet sitter = 2 weeks

The amount Mariah previously saved = $70.99

The amount Maria spent = $12.25

The amount Mariah put in her savings account = 1/4 of the remaining (balance) money

Therefore, we have;

The amount placed in Mariah's savings account, S, is given as follows;

Step 1: S = [($32.75 × 2) + $70.99 - $12.25] × 1/4

Step 2: S = [($65.5 × 2) + $70.99 - $12.25] × 1/4

Step 3: S = [($136.49) - $12.25] × 1/4

Step 4: S = $124.24 × 1/4

Step 5: S = $31.06

The amount Mariah puts in her saving's account = $31.06 and the step Mariah first makes an error is Step 3 where what she put down was as follows;

Step 3: S = $136.49 - $3.0625 × 1/4

2) She can correct the error by completing the calculation of the operation within the parenthesis in Step 2, before multiplying by the factor 1/4.

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