Question

Suppose that y is directly proportional to x and that y = 10 when x = 3. Complete parts (a) and (b). (a) Find the constant of proportionality k. (b) Use y = kx to find y when x = 6.​

Answer 1

For this case we have that if "y" varies directly with "x", then it is true that:

$y = kx$

Where:

k: It is the constant of proportionality

We have according to the data that:

$10 = k (3)$

We find the value of "k":

$k = \frac {10} {3}$

Having "k", we find "y" when $x = 6$:

$y = \frac {10} {3} (6)\\y = \frac {60} {3}\\y = 20$

ANswer:

$k = \frac {10} {3}\\y = 20$