Question

Part A

A scientist needs 10 liters of a 20% acid solution for an experiment, but she has only a 5% solution and a 40% solution. To the nearest tenth of
a liter, about how many liters of the 5% and the 40% solutions should she mix to get the solution she needs?
Choose the equation to match the situation
O A. (0.20) (10) = 0.05x + 0.40x
B. (0.20)(10) = 0.05x +0.40(10 – X)
OC. (0.20) (10) = 0.05(10) + 0.40(10 - x)
O D. (0.20)(10) = 0.05(10 - x) + 0.40(10 - x)
Part B
Solution
liters of 5% and
liters of 40%

Answer 1

• Part A Option B
• Part B 5.71 l and 4.29 l

Explanation:

Part A

Let x be the volume of 5% solution

Then the volume of 40% solution is

• 10 - x

Amount of acid is 10*0.20 for resultant solution, x*0.05 for 5% solution and (10- x)*0.40 is for 40% solution:

• 10*0.20 = x*0.05 + (10 - x)*0.40

Correct equation is B.

Part B

Solving

• 2 = 0.05x + 4 - 0.4x
• 0.35x = 2
• x = 2/0.35
• x = 5.71 l of 5% solution

and

• 10 - x = 10 - 5.71 = 4.29 l of 40% solution