Select the correct answer.

This rational inequality can be used to determine the number of seconds, [tex]x[/tex], that a beginning ice-skater can skate before losing his or her footing:

[tex]\frac{x}{x-6}\ \textgreater \ 13[/tex]

If Charlene has never ice-skated before, which inequality describes the number of seconds she can expect to skate before losing her footing?

A. [tex]6 \ \textgreater \ x \ \textgreater \ 6.5[/tex]
B. [tex]x \ \textless \ 0[/tex]
C. [tex]6 \ \textless \ x \ \textless \ 6.5[/tex]
D. [tex]x \ \textless \ 6[/tex]



Answer :

To solve the given inequality [tex]\(\frac{x}{x-6} > 13\)[/tex], let's follow these steps:

1. Rewrite the Inequality:
[tex]\[ \frac{x}{x-6} > 13 \][/tex]

2. Eliminate the Denominator:
To eliminate the denominator, multiply both sides by [tex]\((x-6)\)[/tex]. But since [tex]\(x-6\)[/tex] could be positive or negative, we need to consider two cases based on the sign of [tex]\(x-6\)[/tex].

[tex]\[ \text{Case 1: } x > 6 \quad \text{(positive denominator)} \][/tex]
[tex]\[ \frac{x}{x-6} > 13 \implies x > 13(x - 6) \][/tex]
[tex]\[ x > 13x - 78 \][/tex]
[tex]\[ x - 13x > -78 \][/tex]
[tex]\[ -12x > -78 \][/tex]
[tex]\[ x < \frac{78}{12} \quad \implies x < 6.5 \][/tex]

Therefore, for [tex]\(x > 6\)[/tex], we have [tex]\(6 < x < 6.5\)[/tex].

[tex]\[ \text{Case 2: } x < 6 \quad \text{(negative denominator)} \][/tex]
[tex]\[ \frac{x}{x-6} > 13 \implies x < 13(x - 6) \][/tex]
[tex]\[ x < 13x - 78 \][/tex]
[tex]\[ x - 13x < -78 \][/tex]
[tex]\[ -12x < -78 \][/tex]
[tex]\[ x > \frac{78}{12} \quad \implies x > 6.5 \][/tex]

However, since [tex]\(x\)[/tex] cannot be both greater than 6.5 and less than 6 at the same time, this case does not provide a valid solution. Therefore, there is no solution for [tex]\(x < 6\)[/tex].

3. Combine Results:
After reviewing the cases, the valid interval where [tex]\(\frac{x}{x-6} > 13\)[/tex] holds true is [tex]\(6 < x < 6.5\)[/tex].

Thus, the correct inequality describing the number of seconds Charlene can expect to skate before losing her footing is:

[tex]\[ \boxed{6 < x < 6.5} \][/tex]

The correct answer is:
C. [tex]\(6 < x < 6.5\)[/tex]