Question 565209
Solution A
Amount = x 
Concentration =25% = 0.25


Solution B
Amount = 200 
Concentration =4% = 0.04


Resultant Solution
Amount = 200+x 
Concentration =10% = 0.1


[Amount Solution A * Concentration A] + [Amount Solution B * Concentration of B]+ [Amount Solution B * Concentration of B] = Amount of Resultant * Concentration of resultant

(0.25)(x)+(200)(0.04)=(200+x)(0.1)
0.25x+8=20+0.1x
0.25x-0.1x=20-8
0.15x=12
0.15x/0.15=12/0.15
x=80





Solution A
Amount = x = 80 centiliters
Concentration =25% = 0.25


Solution B
Amount = 200 centiliters
Concentration =4% = 0.04


Resultant Solution
Amount = 200+x = 200+80 = 280 centiliters
Concentration =10% = 0.1




80 centiliters of a 25% acid solution must be added to 200 centiliters of a 4% acid solution to make a 10% acid solution.