Question 971719
let' say the other solution is x% concentrate.
Now for, 1 oz of original solution, amount of concentrate = 0.4 oz
For 8 oz of other solution, amount of concentrate = 8*(x/100) oz
So, in final solution,
amount of concentrate is (0.4 + 8x/100) oz in total (1+8)oz of solution.
So final concentration is {(0.4 + 8x/100)/9} *100%