7n2 + 9k2 + 6 6n Submit

A lab technician needs 60mL of 25% acid solution for a certain experiment , but he has only 10% solution and 40% solution. How m

V125BC [204]

Answer:

10%: 30 mL
40%: 30 mL

Step-by-step explanation:

The needed concentration is exactly halfway between the available concentrations, hence they must be mixed equally.

He should mix 30 mL each of the 10% and 40% solutions.

_____

The first step in solving any problem is to look at the given information, and at what is being asked for. Here, the mix that is being asked for is exactly halfway between the given concentrations, so you know without any further contemplation that the mix will be 50%/50% of each.

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If the mix were something else, there are several ways the problem can be solved. I like to use a diagram that puts the available concentrations on the left in a column with the highest on top, the needed concentration in the next column in the middle, and the differences of these numbers on the diagonals in the right column.

Example: if the needed mix is 15%, the diagram would look like ...

40 5

15

10 25

The numbers on the right tell you the proportions required (5:25 = 1:5). For this example, you need 1 part 40% solution and 5 parts 10% solution to make a mix that is 15%. That's a total of 6 parts, so each "part" is 10 mL for 60 mL of solution.

We chose this example so every number in the diagram is different, so you could see how the instructions for use apply.

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Another way to solve this is to let a variable represent the amount needed of the highest concentration. If we let that variable be x, for the given problem, we can write the equation for the amount of acid in the mix as ...

40%(x) + 10%(60 -x) = 25%(60)

0.30x = 9 . . . . . . . . subtract 6, simplify

x = 9/0.30 = 30 . . . . . mL of 40% solution

6 0

3 years ago

PLEEEASSSSEEEEE HELPPPP!!!! A rectangular prism has a length of 12 in., a width of 5 in., and a height of 4 1/4 in. The prism is

Aleonysh [2.5K]

Answer:

16320

solution: 12 / 1/4 = 3.

4 divided by 1/4 = 20

4 1/4 divided by 1/4 = 17.

3 x 20 x 17 =

the answer is 16320.

3 0

3 years ago

Evaluate 2/ 3 ÷ 4 /5 Give your answer as a fraction in its simplest form.

gulaghasi [49]

Step-by-step explanation:

Our problem:

$\frac{2}{3} \div \frac{4}{5} = unknown$

How to solve?

Find the reciprocal (opposite) of 4/5, then multiply. Simplify if necessary.

Find the reciprocal:

$\frac{2}{3} \times \frac{5}{4} = unknown$

Multiply:

$\frac{2}{3} \times \frac{5}{4} = \frac{10}{12}$

Simplify:

$\frac{10 \div 2}{12 \div 2} = \frac{5}{6}$

5/6 is your answer.

7 0

3 years ago

Triphasil-28 birth control tablets are taken sequentially, 1 tablet per day for 28 days, with the tablets containing the followi

bazaltina [42]

Answer:

1.925mg of levonorgestrel and 0.68mg of ethinyl estradiol are taken during the 28-day period.

Step-by-step explanation:

The total milligrams of levonorgestrel is:

$L = L_{1} + L_{2} + L_{3}$

In which $L_{1}, L_{2}$ and $L_{3}$ are the number of miligrams of levonorgestrel taken in each phase.

The total milligrams of ethinyl estradiol is:

$E = E_{1} + E_{2} + E_{3}$

In which $E_{1},E_{2}$ and $E_{3}$ are the number of miligrams of ethinyl estradiol taken in each phase.

We can solve this by phase.

Phase 1: 6 tablets, each containing 0.050 mg of levonorgestrel and 0.030 mg ethinyl estradiol

In this phase,

$6*0.050mg = 0.30mg$ of levonorgestrel and $6*0.030mg = 0.18mg$ of ethinyl estradiol are taken.

So $L_{1} = 0.30$ and $E_{1} = 0.18$

Phase 2: 5 tablets, each containing 0.075 mg of levonorgestrel and 0.040 mg ethinyl estradiol

In this phase,

$5*0.075mg = 0.375mg$ of levonorgestrel and $5*0.040mg = 0.20mg$ of ethinyl estradiol are taken.

So $L_{2} = 0.375$ and $E_{2} = 0.20$

Phase 3: 10 tablets, each containing 0.125 mg of levonorgestrel and 0.030 mg ethinyl estradiol

In this phase,

$10*0.125mg = 1.25mg$ of levonorgestrel and $10*0.030mg = 0.30mg$ of ethinyl estradiol are taken.

So $L_{3} = 1.25$ and $E_{3} = 0.30$

The total milligrams of levonorgestrel is:

$L = L_{1} + L_{2} + L_{3} = 0.30 + 0.375 + 1.25 = 1.925$

The total milligrams of ethinyl estradiol is:

$E = E_{1} + E_{2} + E_{3} = 0.18 + 0.20 + 0.30 = 0.68$

1.925mg of levonorgestrel and 0.68mg of ethinyl estradiol are taken during the 28-day period.

6 0

3 years ago

A moving company charges $0.70 per pound for a move from New York to Florida. A family estimates that their belongings weigh abo

mamaluj [8]

First, how many pounds are equal to 1 ton? 2000

Then, $0.70 x 2000 pounds

So, the cost to move is $1,400

Yep. It's that simple. :)

5 0

3 years ago

7n2 + 9k2 + 6 6n Submit​

7n2 + 9k2 + 6 6n Submit