Question

Suppose f(x) varies directly with x and f(x) = 24 when x = 2.
What is the value of f(x) when x = 6?

1/12
1/2
48
72

Answer 1

Answer: D

Step-by-step explanation:

varies directly means $\frac{f(x)}{x} = k$

Solve for k: $\frac{f(x)}{x} = k$

                   $\frac{24}{2} = k$

                     12 = k

Next, input the k-value above and solve for f(x):

$\frac{f(x)}{x} = k$

$\frac{f(x)}{6} = 12$

$(6)\frac{f(x)}{6} = 12(6)$

f(x) = 72