Final answer:
None of the given options (A, B, C, D) correctly express the number 6.72 as a fraction in simplest form. The correct simplified fraction of 6.72 is 6 18/25, which is not listed among the choices.
Step-by-step explanation:
The student asked which number expresses 6.72 as a fraction in simplest form. To convert the decimal 6.72 to a fraction, we separate the whole number from the decimal, resulting in 6 and 0.72. Next, we express 0.72 as a fraction. Since 0.72 has two decimal places, the denominator should be 100, making it 72/100. We then simplify the fraction by finding the greatest common divisor (GCD) of 72 and 100, which is 4. Dividing both numerator and denominator by 4, we get 18/25. Therefore, the decimal 6.72 can be written as the mixed number 6 18/25.
However, the options given (A through D) do not include 6 18/25, so we need to see which provided option matches the simplified fraction. Option B, which is 6 7/10, would be equivalent to 6.70, not 6.72, and option D 6 3/4 is equal to 6.75. Both option A, 6 3/5, and option C, 6 18/15 do not match the decimal, with option A being equivalent to 6.60 and option C being reducible to 7 3/15 (or 7 1/5, equivalent to 7.20). Therefore, strictly speaking, none of the given options correctly represent 6.72 as a fraction in the simplest form.