BEST estimate of this amount is . Correct option A. 2 x 10^7 .
<u>Step-by-step explanation:</u>
Here we have , Hoover Dam spans the Colorado River on the Nevada-Arizona state line. For its construction, the federal government purchased 21,670,000 pounds of gates and valves. We need to find BEST estimate of this amount . Let's find out:
21,670,000 pounds
⇒ 21,670,000 pounds
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Now, Rounding of 2.167 we get 2 ,So
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Hence , BEST estimate of this amount is . Correct option A. 2 x 10^7 .