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 .

Step-by-step 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 .