After completing the fraction division StartFraction 7 Over 3 EndFraction divided by StartFraction 2 Over 9 EndFraction, Bai used the multiplication below to check his work.

StartFraction 21 Over 2 EndFraction times StartFraction 2 Over 9 EndFraction = StartFraction 42 Over 18 EndFraction = StartFraction 7 Over 3 EndFraction

Which is the most accurate description of Bai’s work?
Bai found the correct quotient and checked his work using multiplication correctly.
Bai found the correct quotient but checked his work using multiplication incorrectly.
Bai found an incorrect quotient but checked his work using multiplication correctly.
Bai found an incorrect quotient and checked his work using multiplication incorrectly.

1 answer

To evaluate Bai's work, we need to verify both the division he completed and the multiplication he used to check his work.

  1. Division of Fractions: To divide fractions, we multiply by the reciprocal. Therefore: \[ \frac{7}{3} \div \frac{2}{9} = \frac{7}{3} \times \frac{9}{2} \] This simplifies to: \[ = \frac{7 \times 9}{3 \times 2} = \frac{63}{6} = \frac{21}{2} \]

    So, the correct quotient of \(\frac{7}{3} \div \frac{2}{9}\) is \(\frac{21}{2}\).

  2. Checking the Work: Bai attempted to check his work using the equation: \[ \frac{21}{2} \times \frac{2}{9} \] This simplifies to: \[ = \frac{21 \times 2}{2 \times 9} = \frac{42}{18} = \frac{7}{3} \]

    Here, he is verifying \(\frac{21}{2}\) was the correct quotient by multiplying it by \(\frac{2}{9}\), which simplifies correctly back to \(\frac{7}{3}\).

Now, examining Bai’s process:

  • He found the correct quotient of \(\frac{7}{3} \div \frac{2}{9}\) resulted in \(\frac{21}{2}\).
  • He checked his work correctly, as \( \frac{21}{2} \times \frac{2}{9} \) indeed equals \(\frac{7}{3}\).

Based on this assessment, the most accurate description of Bai’s work is:

Bai found the correct quotient and checked his work using multiplication correctly.