Question 169246
x+y=1000: eq 1   where x is the amount of 55 cent mixture and y is the amount 
of 75 cent mixture
:
.55x+.75y=.6(1000)...eq 2

lets take the y value of eq 1 which is y=1000-x and plug it into eq 2.
:
.55x+.75(1000-x)=600
:
.55x+750-.75x=600
:
.2x=150

{{{highlight(x=750)}}} kg of 55 cent candy
{{{highlight(1000-750=250)}}}kg of 75 cent candy