Answer:
$20M
Explanation:
You want the "natural breakpoint" for a lease that specifies rent is the maximum of $5 per square foot for 120,000 square feet, or 3% of sales.
Minimum rent
The minimum rent is ($5/ft²)×(120000 ft²) = $600,000.
Breakpoint
The amount of sales that makes $600,000 equal to 3% of sales is ...
$600000 = 0.03s
s = $600000/0.03 = $20,000,000
The "natural breakpoint" is $20M in sales.
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Additional comment
When sales exceeds $20M, 3% of sales is more than $5/ft², so the rent will be based on sales.