Final answer:
By analyzing the clues, we know Ashton's number is the 10th multiple of Ivy's number, which must be the highest common factor of 20 and 28 greater than 2; hence Ashton's number is 40.
Step-by-step explanation:
The question revolves around determining Ashton's number based on the clues provided. We know that both 20 and 28 are multiples of Ashton's number, and that this number is also the 10th multiple of Ivy's number. Understanding multiples and the relationship of numerical factors will be crucial to solving this problem. To perform this in my head, I consider the common factors of 20 and 28 that are greater than 2. The highest common factor is 4 which is possibly Ivy's number. Since Ashton's number is the 10th multiple of Ivy's number, we multiply 4 by 10, resulting in 40 as Ashton's number.
Math problems like this demonstrate the universality of mathematics and its rules. The principles that provide answers in mathematics are the same across different cultures and time periods. It's also a testament to the concept that math provides many paths to the same answer, which can be used to check and verify solutions.