Question 309438
a+b=8
a=8-b
x*a+y*b=140
a*x=90
b*y=50
y=50/b
x=y-10
x*a+y*b=140
(50/b-10)(8-b)+50=140
b=2
b=20 
a+20=8
a=-12 discard
b=20 discard
a+2=8
a=6
a = 6,   b = 2,   x = 15,   y = 25