Answer:
$133,000
Step-by-step explanation:
The upper end of the contractor's budget is $297,000. If he has already spent $164,000, he can spend as much as ...
$297,000 -164,000 = $133,000
without exceeding his budget.
He can spend $133,000 more and remain within budget.
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Additional comment
Of course, he'd like to come in at the low end of the cost range, so would be very happy to spend only $71,000 more.