High School

An expression is shown:

[tex]\frac{\left(12 \times 10^2\right)-\left(7 \times 10^2\right)}{\left(8 \times 10^5\right)}[/tex]

Which expression is equivalent?

A. [tex]6.25 \times 10^{-4}[/tex]

B. [tex]6.25 \times 10^{-1}[/tex]

C. [tex]6.25 \times 10^5[/tex]

D. [tex]6.25 \times 10^4[/tex]

Answer :

Let's solve the given expression step-by-step to find which option is equivalent.

The expression given is:

[tex]\[
\frac{(12 \times 10^2) - (7 \times 10^2)}{(8 \times 10^5)}
\][/tex]

1. Calculate the Numerator:

[tex]\((12 \times 10^2) - (7 \times 10^2)\)[/tex]

- First, compute [tex]\(12 \times 10^2 = 1200\)[/tex].
- Then, compute [tex]\(7 \times 10^2 = 700\)[/tex].
- Subtract these results: [tex]\(1200 - 700 = 500\)[/tex].

So, the numerator is [tex]\(500\)[/tex].

2. Calculate the Denominator:

[tex]\((8 \times 10^5)\)[/tex]

This is simply [tex]\(800,000\)[/tex].

3. Form the Fraction and Simplify:

Now, form the fraction using the calculated numerator and denominator:

[tex]\[
\frac{500}{800,000}
\][/tex]

Divide the numerator by the denominator:

[tex]\[
\frac{500}{800,000} = 0.000625
\][/tex]

4. Convert the Result to Scientific Notation:

The result [tex]\(0.000625\)[/tex] can be written in scientific notation. To express it, move the decimal point four places to the right:

[tex]\[
0.000625 = 6.25 \times 10^{-4}
\][/tex]

5. Find the Equivalent Expression:

Comparing with the choices given:

- A. [tex]\(6.25 \times 10^{-4}\)[/tex]
- B. [tex]\(6.25 \times 10^{-1}\)[/tex]
- C. [tex]\(6.25 \times 10^5\)[/tex]
- D. [tex]\(6.25 \times 10^4\)[/tex]

The equivalent expression for the fraction is [tex]\(6.25 \times 10^{-4}\)[/tex].

Therefore, the correct answer is [tex]\(\boxed{A}\)[/tex].