College

Suppose [tex]f[/tex] varies inversely as [tex]g[/tex], and [tex]f = 7[/tex] when [tex]g = 56[/tex]. What is the value of [tex]g[/tex] when [tex]f = 8[/tex]?

A. 64
B. 49
C. 1
D. 392

Answer :

Sure! Let's solve this question step-by-step.

1. Understanding the Problem: We're told that [tex]\( f \)[/tex] varies inversely as [tex]\( g \)[/tex]. This means as one increases, the other decreases. Mathematically, this relationship can be expressed as [tex]\( f \times g = k \)[/tex], where [tex]\( k \)[/tex] is a constant.

2. Finding the Constant [tex]\( k \)[/tex]: We're given that [tex]\( f = 7 \)[/tex] when [tex]\( g = 56 \)[/tex]. Substituting these values into the inverse variation formula:

[tex]\[
7 \times 56 = k
\][/tex]

Multiplying these gives:

[tex]\[
k = 392
\][/tex]

3. Finding the New Value of [tex]\( g \)[/tex] when [tex]\( f = 8 \)[/tex]: We need to find [tex]\( g \)[/tex] when the new value of [tex]\( f \)[/tex] is 8. Using the constant [tex]\( k \)[/tex] we found, the equation becomes:

[tex]\[
8 \times g = 392
\][/tex]

To find [tex]\( g \)[/tex], we divide both sides by 8:

[tex]\[
g = \frac{392}{8}
\][/tex]

Dividing gives:

[tex]\[
g = 49
\][/tex]

4. Conclusion: Therefore, the value of [tex]\( g \)[/tex] when [tex]\( f = 8 \)[/tex] is 49.

The correct answer is B. 49.