Question

1. 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. Which
number is the BEST estimate of this
amount?
A. 2 x 10^7
B. 2 x 10^8
C. 3 x 10^7
D. 3 x 10^8

Answer 1

BEST estimate of this amount is
`2(10^(7))` . Correct option A. 2 x 10^7 .

Explanation:

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

⇒
`21,670,000`

⇒
`2167(10^(4))`

⇒
`2.167(10^(3))(10^(4))`

⇒
`2.167(10^(3+4))`

⇒
`2.167(10^(7))`

Now, Rounding of 2.167 we get 2 ,So

⇒
`2(10^(7))`

Hence , BEST estimate of this amount is
`2(10^(7))` . Correct option A. 2 x 10^7 .