If [tex]$y$[/tex] varies directly as [tex]$x$[/tex], and [tex][tex]$y$[/tex][/tex] is 48 when [tex]$x$[/tex] is 6, which expression can be used to find the value of [tex]$y$[/tex] when [tex][tex]$x$[/tex][/tex] is 2?

A. [tex]y = \frac{48}{6}(2)[/tex]
B. [tex]y = \frac{6}{48}(2)[/tex]
C. [tex]y = \frac{(48)(6)}{2}[/tex]
D. [tex]y = \frac{2}{(48)(6)}[/tex]



Answer :

If [tex]\( y \)[/tex] varies directly as [tex]\( x \)[/tex], it means there is a constant [tex]\( k \)[/tex] such that [tex]\( y = kx \)[/tex].

Given the information:
- [tex]\( y = 48 \)[/tex] when [tex]\( x = 6 \)[/tex], we can find [tex]\( k \)[/tex] as follows:

[tex]\[ 48 = k \cdot 6 \][/tex]

Solving for [tex]\( k \)[/tex]:

[tex]\[ k = \frac{48}{6} \][/tex]

[tex]\[ k = 8 \][/tex]

Now that we have the constant of variation ([tex]\( k = 8 \)[/tex]), we need to find the value of [tex]\( y \)[/tex] when [tex]\( x = 2 \)[/tex].

Using the direct variation equation [tex]\( y = kx \)[/tex]:

[tex]\[ y = 8 \cdot 2 \][/tex]

[tex]\[ y = 16 \][/tex]

To match this result with the expressions given in the problem:

[tex]\[ y = \frac{48}{6} \cdot 2 \][/tex]

Therefore, the correct expression to use is:

[tex]\[ y = \frac{48}{6} (2) \][/tex]

The other expressions are incorrect because:
- [tex]\( y = \frac{6}{48} (2) \)[/tex] does not use the correct ratio.
- [tex]\( y = \frac{(48)(6)}{2} \)[/tex] incorrectly multiplies and then divides by [tex]\( 2 \)[/tex].
- [tex]\( y = \frac{2}{(48)(6)} \)[/tex] incorrectly places [tex]\( 48 \)[/tex] and [tex]\( 6 \)[/tex] in the denominator.

So the expression that can be used to find the value of [tex]\( y \)[/tex] when [tex]\( x \)[/tex] is 2, is:

[tex]\[ y = \frac{48}{6} (2) \][/tex]

The value of [tex]\( y \)[/tex] when [tex]\( x = 2 \)[/tex] is [tex]\( 16 \)[/tex], and the corresponding expression is [tex]\( y = \frac{48}{6} (2) \)[/tex].