The minimum number of employees to be covered by the plan is 630.
An eligible pension plan must pass the ratio percentage test to qualify for preferential income-tax treatment. According to this criterion, the ratio of highly compensated employees covered by the plan to lower-paid employees covered by the plan must be at least 70%.
This test will be the most common method of passing the coverage testing, and it shows that at least 70% of the users are benefiting.
In the given question, out of 1000 employees, 100 of them are highly compensated and therefore for the remaining 900, the ratio-percentage test for their coverage will be,
= 70% of 900 employees
= 630 employees
Therefore, 630 employees, must be covered by the plan, so that it satisfies the ratio-percentage test.
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