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Jeremiah answers 90% of the questions on his test correctly. There are 40 questions on the test. Jeremiah writes the expression 40−( 1/10×40) to determine the number of questions answered correctly. Which is an equivalent expression?

A) 40−4
B) 40−0.4×40
C) 40−4.4
D) 40−4×0.1×40

User Szkj
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Final answer:

The equivalent expression to Jeremiah's calculation of the number of questions he answered correctly on a test, which is 40 - (1/10 × 40), is Option A) 40 - 4.

Step-by-step explanation:

The student, Jeremiah, is working with percentages and algebraic expressions in the context of a math problem. His approach to finding the number of questions he answered correctly on a test with 40 questions is to subtract 10% of the total questions from the total because he answered 90% correctly. The expression 40 - (1/10 × 40) simplifies to 40 - 4, which represents the 36 questions he answered correctly. Now, to determine which equivalent expression represents the same calculation, we can examine the provided options:

  • A) 40 - 4: This is simply a direct subtraction without involving percentages or decimal multiplication, and it is equivalent to Jeremiah's expression because 1/10 of 40 is 4.
  • B) 40 - 0.4 × 40: This would result in subtracting 16 from 40, which is not equivalent to Jeremiah's expression.
  • C) 40 - 4.4: This implies subtracting 4.4 from 40, not an equivalent expression to Jeremiah's since he needs to subtract 4, not 4.4.
  • D) 40 - 4 × 0.1 × 40: This option is redundant and would result in subtracting a number much larger than 4 from 40, thus it is not equivalent to Jeremiah's expression.

Therefore, the equivalent expression to 40 - (1/10 × 40) is Option A) 40 - 4.

User Jacefarm
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