Question 179768
so let N be the number of liters of 40% solution.
:
let x and y be the amount of mixture of 60% and 10% solutions respectively
:
x+y=N........eq 1
.6x+.1y=.4N..eq 2
:
rewrite eq 1 to x=N-y and plug that value into eq 2
:
.6(N-y)+.1y=.4N
:
.6N-.6y+.1y=.4N
:
-.5y=-.2N
:
y=.4N
:
x=N-.4N=.6N
:
x/y=.6N/.4N=3/2
: 
so the ratio is 3 to 2