Question

Start with 9 multiply by 5 the answer is 45 is bigger than 9 Ellens calculayions are correct but her rule doesn't always work for what numbers will Ellen's rule work? For what numbers will Ellen's rule not work

Answer 1

So, this rule is not applicable if the number b is less than 1.

Explanation:

Ellen's Rule is

9 multiply by 5 the answer is 45 which is more than 9

This rule is generalised as

A x b > A if b is > 1

Here, A is 9 and b is 5 and it is more than 1 so, A x b = 45 > A

now

A x b < A if b is < 1

If b = 0.5, A = 9

9 x 0.5 = 4.5 < 9

So, this rule is not applicable if the number b is less than 1.