Suppose y is directly proportional to x

If y = 8 when x = 20, determine the value of k such that y = kx

k = 2/5

Step-by-step explanation:

from the question, we have that Suppose y is directly proportional to x

mathematically'

y ∝ x

y = kx ... where k is the constant of proportionality

given that y = 8, x = 20 where k = ?

so from,

y = kx

we are going to make k the subject of the formula by getting rid of x away from k.

y = kx

divide both sides by x

y/x = kx/x

y/x = k

therefore k = y/x

k = 8/20

k = 2/5

therefore the value of k which is the constant of proportionality in this expression is given to be 2/5