Question 32853
First, we set up our general equation. Because y is directly proportional to x, we have: y = cx 
where c is the constant of proportionality. In other words, when x goes up, y goes up, and when x goes down, y goes down. 
 

Here m varies directly with n and K = constant of proportionality

so the equation will be m = nk

here the values are m = 144 and n = 8

so simply substitute those values in the equation to get the value of k

144 = (8)* k
therefore k = 144/8 = 18

k = 18