Question 366975
6 lbs. of Mixture A number of pounds be x
4 lbs of Mixture B  number of pounds be y
and pays $17. 
6x+4y=17.....................................1

Another customer reverses the proportions 
and pays a dollar more.   
6y+4x=18.....................................2
...
multiply 1 by -4 & 2 by 6
-24x-16y=-68
36y+24x=108
..
add up 
20y=40
/20
y = 2 price of Mixture B
plug value of y in 
6x+4y=17
6x+8=17
6x=9
/6
x= 3/2 the price of mixture A
...
m.ananth@hotmail.ca