Problem: seed mixture x is 40 percent ryegrass and 60 percent bluegrass by weight ; seed mixture y is 25 percent ryegrass and 75 percent fescue . if a mixture of x and y contains 40 percent ryegrass , what percent of the weight of this mixture is x ? 
Options: a ) 100 % , b ) 33.33 % , c ) 40 % , d ) 50 % , e ) 66.66 %
a