You need a 45% alcohol solution. On hand, you have a 350 mL of a 15% alcohol mixture. You also have 70% alcohol mixture. How much of the 70% mixture will you need to add to obtain the desired solution?

You will need
________ mL of the 70% solution

Juan needs to mix a 10% acid solution with a 50% acid solution to create 100 millileters of a 34% solution. How many millileters of each solution must Juan use?

______ millileters of 10% solution and
________ millileters of 50% solution.

amount of the 70% solution needed ---- x ml

So your final amount will be x + 350 ml
.17(350) + .70x = .45(350+x)

suggestion: multiply each of the 3 terms by 100 to get rid of those decimals
17(350) + 70x = 45(350+x)

now just solve for x

To calculate the amount of the 70% alcohol mixture needed, we can use the following formula:

(total amount of solution) x (desired concentration) = (amount of 15% mixture) x (concentration of 15% mixture) + (amount of 70% mixture) x (concentration of 70% mixture)

Let's plug in the given values:
(total amount of solution) = 350 mL + x (unknown amount of 70% mixture)
(desired concentration) = 45%
(amount of 15% mixture) = 350 mL
(concentration of 15% mixture) = 15%
(concentration of 70% mixture) = 70%

Now we can rearrange the formula to solve for x:
350 mL + x = (350 mL * 0.15) + (x * 0.70)

Next, we can simplify the right side of the equation:
350 mL + x = 52.5 mL + 0.7x

Now, let's isolate the x term:
x - 0.7x = 52.5 mL - 350 mL
0.3x = -297.5 mL

Finally, we can solve for x:
x = (-297.5 mL) / 0.3 ≈ 991.7 mL

Therefore, you would need approximately 991.7 mL of the 70% alcohol mixture to obtain the desired solution.

To solve this problem, we need to find out how much of the 70% alcohol mixture is required to obtain a 45% alcohol solution.

Let's first calculate the amount of alcohol in the 15% solution.

Amount of alcohol in the 15% solution = 350 mL * 15/100 = 52.5 mL

Let's assume we need x mL of the 70% alcohol solution.

Amount of alcohol in the x mL of the 70% alcohol solution = x mL * 70/100 = 0.7x mL

Now, we can set up an equation to determine the total amount of alcohol in the final solution:

Total amount of alcohol = amount of alcohol in the 15% solution + amount of alcohol in the 70% solution

Since we want a 45% alcohol solution, the total amount of alcohol will be 45% of the final volume.

Total amount of alcohol = 350 mL + 0.7x mL

Setting up the equation:

52.5 mL + 0.7x mL = (45/100) * (350 mL + x mL)

Simplifying the equation:

52.5 + 0.7x = 0.45 * (350 + x)

52.5 + 0.7x = 157.5 + 0.45x

Subtracting 0.45x from both sides:

0.25x = 105

Dividing both sides by 0.25:

x = 420

Therefore, you will need 420 mL of the 70% alcohol solution to obtain the desired 45% alcohol solution.