Kate Farb-Johnson’s single word change test

I’ve always wanted a rule of thumb to aid in spotting word problems that cause above-average reading difficulties. Now I’ve found one:

What are word problems really testing?

Unfortunately for his argument, the most likely reason to get this problem wrong is misreading it. Of the 4 incorrect answers, 3 of them can be obtained by changing/misreading a single word of the problem. Answer A)9 comes from adding “more” between “many” and “employees” in the question. Answer B comes from changing “increased” to “decreased”. Answer E comes from dropping the word “percent” after the number 10.