When you divide by a fraction, it is equivalent to multiplying by its reciprocal. In this case, dividing by 8/5 means you are actually multiplying by 5/8. This results in each group being smaller, specifically 5/8 of the original size. Consequently, since the groups are smaller, you can fit more groups into the same total amount, which is why there would be 8/5 as many groups. This concept is crucial in understanding how division by fractions works in mathematics.