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UNO [17]
2 years ago
8

You need a 70% alcohol solution. On hand, you have a 420 mL of a 85% alcohol mixture. How much pure water will you need to add t

o obtain the desired solution?
Mathematics
1 answer:
Nimfa-mama [501]2 years ago
6 0

Answer:

Pure water =74.1 mL

Step-by-step explanation:

You need 420 mL of a 70% alcohol solution.

420 mL of solution and 70% of it should be alcohol.

So,

420 * 70/100 mL

= 420 * 0.7

= 294 mL of alcohol and the rest should be water.

On hand, you have a 85% alcohol mixture.

The alcohol can only come from the 85% mixture. So, how much of 85% alcohol do we need to get 294 mL of alcohol:

Let

y = alcohol solution needed

85% of y = 294

85/100 * y = 294

y = 294 ÷ 85/100

y = 294 × 100/85

y = 29,400/85

y = 345.88235294117

Approximately, 345.9mL

The rest of 420 mL solution has to be pure water

Pure water = 420 mL - 345.9mL

= 74.1 mL

Pure water =74.1 mL

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Shelly is trying to improve her running time for a track race. She ran the first race in 43.13 seconds. Her time was 43.1 second
saul85 [17]
<h3>The time in fourth race is 43.04 seconds</h3>

<em><u>Solution:</u></em>

Given that,

Shelly is trying to improve her running time for a track race

She ran the first race in 43.13 seconds

Her time was 43.1 seconds in the second race and 43.07 seconds in the third race

<em><u>Therefore, pattern is:</u></em>

43.13, 43.1, 43.07 , ..

<em><u>Find the difference between each terms</u></em>

d = 43.13 - 43.1 = 0.03

d = 43.1 - 43.07 = 0.03

Thus the difference is same

<em><u>If this pattern continues what will shellys time be in the fourth race?</u></em>

Fourth race = third race - 0.03

Fourth race = 43.07 - 0.03 = 43.04

Thus the time in fourth race is 43.04 seconds

8 0
3 years ago
Which answer choice correctly solves the division problem
Orlov [11]

Answer:

The answer is D.

\frac{938}{12}  =  \frac{469}{6}  \\  = 78 \frac{1}{6}

3 0
2 years ago
The team ran
juin [17]

The team ran 2 miles.

Step-by-step explanation:

Step 1; The track is \frac{3}{4} miles long and the team ran 2\frac{2}{3} laps on it. To calculate the distance run we multiply the number of laps ran with the distance on each lap.

Distance run = Number of laps × Distance on each lap.

Step 2; We convert 2\frac{2}{3} from a mixed fraction into an improper fraction. To do this, we multiply the whole number with the denominator of the fraction and add with it the numerator of the same fraction whereas the denominator remains unchanged. To convert the fraction 2\frac{2}{3} = ((2 × 3) + 2) / 3 = \frac{8}{3}.

Distance run = Number of laps × Distance on each lap = \frac{8}{3} × \frac{3}{4} = \frac{8}{4} = 2 miles.

3 0
3 years ago
Read 2 more answers
20 plus 2 x divided by 5 subtract x
irina [24]
20+2x/5-x
Start by writing it as a fraction

20 + 2/5x (fraction) - x
Next you calculate the difference

20 - 3/5x (fraction) is the answer
3 0
3 years ago
Write Equivalent Fractions
Viktor [21]

Answer:

Step-by-step explanation:

Find equivalent fractions. Enter a fraction, mixed number or integer to get fractions that are equivalent to your input. Example entries:

Fraction - like 2/3 or 15/16

Mixed number - like 1 1/2 or 4 5/6

Integer - like 5 or 28

What are Equivalent Fractions?

Equivalent fractions are fractions with different numbers representing the same part of a whole. They have different numerators and denominators, but their fractional values are the same.

For example, think about the fraction 1/2. It means half of something. You can also say that 6/12 is half, and that 50/100 is half. They represent the same part of the whole. These equivalent fractions contain different numbers but they mean the same thing: 1/2 = 6/12 = 50/100

How to Find Equivalent Fractions

Multiply both the numerator and denominator of a fraction by the same whole number. As long as you multiply both top and bottom of the fraction by the same number, you won't change the value of the fraction, and you'll create an equivalent fraction.

Example Equivalent Fractions

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34×22=68

34×33=912

34×44=1216

34×55=1520

34×66=1824

Therefore these are all equivalent fractions:

34=68=912=1520=1824

Note that if you reduce all of these fractions to lowest terms, they equal 3/4.

For additional fraction help see our Fractions Cal

3 0
2 years ago
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