Question 900887
a+b=100,
6*a+3*b=5*100
a=100-b
6*(100-b)+3*b=500
600-6b+3*b=500
-3*b=-100
b=33 1/3
a=100-b
a=66 2/3 lb  at $6.00 b=33 1/3 lb at $3.00
check
6*66.6666667+3*33.3333333=5*100
400.0+100.0=500
500.0=500
ok