Question:
A certain store sells only black shoes and brown shoes. In a certain week, the store sold x black shoes and y brown shoes. If 2/3 of all shoes sold that week were black, which of the following expressions represents the value of y, in terms of x?


Solution:

2/3 of all shoes sold were black
=> Out of a total of 3 shoes, 2 were black , and hence, 1 was brown

Since the store sold x black shoes and y brown shoes, we have:

x equivalent to 2 and y equivalent to 1
=> y = x/2

Answer B
_________________

let total shoes x+y = 6
so black ; x ; 4 and y = 2
from given options ; plugin x =4 and we get y value at x/2
IMO B

We can create the equation:

x = (2/3)(x + y)

3x = 2(x + y)

3x = 2x + 2y

x = 2y

x/2 = y

Answer: B


_________________

Total no. of shoes sold in the week =(x+y)
2/3rd of those sold shoes were black . So 2/3(x+y) = x.
Solving this gives y= x/2.
Option B.