Solve. 9) How many liters of water must be added to 50 L of a 30%acid solution i
ID: 3094836 • Letter: S
Question
Solve.9) How many liters of water must be added to 50 L of a 30%acid solution in order to produce a 20% acid solution?
12) A grocer mixes 2 kinds of nuts. One kind costs $5.00/kgand the other $5.80/kg. How many kilograms of each type are neededto make 40 kg of a blend worth $5.50/kg?
Thank you! Sorry for having 2 problems, but I really need thehelp.
9) How many liters of water must be added to 50 L of a 30%acid solution in order to produce a 20% acid solution?
12) A grocer mixes 2 kinds of nuts. One kind costs $5.00/kgand the other $5.80/kg. How many kilograms of each type are neededto make 40 kg of a blend worth $5.50/kg?
Thank you! Sorry for having 2 problems, but I really need thehelp.
Explanation / Answer
9) Set up the 30 percent acid solution as a fraction of the 50Liters of acid and water solution. 15/50 = Acidconcentration When we add water our new Acid concentration becomes 15/(50+W) withW being the amount of water added. If we set this equationequal to 0.20 we can figure out the amount of water that needs tobe added. 15/(50+W) = 0.20 15 = 0.20(50+W) 15 = 10 + W/5 5 = W/5 25 = W (This is the amount of water need in liters to obtain a 20%acid solution) 12) First define your variables: A = the amount of $5.00/kg nuts B = the amount of $5.80/kg nuts Now set up two equations 5A + 5.8B = 40(5.5) A + B = 40 Now solve for A A + B = 40 A = 40 - B Now substitute this into the first equation and solve forB 5A + 5.8 B = 40(5.5) 5(40 - B) + 5.8B = 220 200 - 5B + 5.8B = 220 0.8B = 20 B = 25 (The amount of B nuts needed) Now solve for A with B=25 A = 40 - B A = 40 - 25 A = 15 (This is the amount of A nuts needed)