Help me i’ll give brainliest

A scientist need 10 L of a 20% acid solution for an experiment where she had only a 5% solution and a 40% solution to the neares

andrezito [222]

Answer:

Amount of 5% solution = 5.7 Litres

Amount of 40% solution = 4.3 Litres

Step-by-step explanation:

First, of all, let x be the amount of 5% solution used

Since, the scientist needs 10 L of solution, then;

Let 10 - x be the amount of 40% solution used

Now, we are told that she needs 10 L of a 20% acid solution.

This means that;

5%x + 40%(10 - x) = 20%(10).

Simplifying this gives;

0.05x + 0.40(10 - x) = 0.20 × 10

Expanding the bracket gives;

0.05x + 4 - 0.4x = 2

0.4x - 0.05x = 4 - 2

0.35x = 2

x = 2/0.35

x ≈ 5.7 litres

Thus, she will need to mix 5.7 liters of the 5% solution.

Since 10 - x be the amount of 40% solution used , then;

the amount of 40% solution = 10 - 5.7 = 4.3 litres

4 0

3 years ago

I am having trouble 2(10-13x)=-34x+60

morpeh [17]

Simplifying 2(10 + -13x) = -34x + 60
(10 * 2 + -13x * 2) = -34x + 60
(20 + -26x) = -34x + 60
Reorder the terms: 20 + -26x = 60 + -34x
Solving 20 + -26x = 60 + -34x
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '34x' to each side of the equation. 20 + -26x + 34x = 60 + -34x + 34x
Combine like terms: -26x + 34x = 8x 20 + 8x = 60 + -34x + 34x
Combine like terms: -34x + 34x = 0 20 + 8x = 60 + 0 20 + 8x = 60
Add '-20' to each side of the equation. 20 + -20 + 8x = 60 + -20
Combine like terms: 20 + -20 = 0 0 + 8x = 60 + -20 8x = 60 + -20
Combine like terms: 60 + -20 = 40 8x = 40
Divide each side by '8'. x = 5
Simplifying x = 5

7 0

3 years ago

The average number of newspapers for sale in an airport stand is 15. SD is 6. The average age of the pilots is 36 and SD is 4. W

balu736 [363]

Answer:

The average age of pilots has a lower coefficient of variation, so it is the most consistent data set.

Step-by-step explanation:

The coefficient of variation is used to measure consistency of a data set. It is the standard deviation divided by the mean. The higher the coefficient of variation, the more variable, that is, the least consistent the data set is.

The average number of newspapers for sale in an airport stand is 15. SD is 6.

The consistency is:

$C = \frac{6}{15} = 0.4$

The average age of the pilots is 36 and SD is 4.

The consistency is:

$C = \frac{4}{36} = 0.11$

The average age of pilots has a lower coefficient of variation, so it is the most consistent data set.

4 0

3 years ago

I need help solving #9 & #11! It's geometry but I'm just really stuck

Vikentia [17]

Answer:

9)x=11 y=3

11)x=18 y=5

Step-by-step explanation:

9) 9x+25=13x+19 13x-19+17y+5=180

9x+44=13x 129+17y=180

44=4x 17y=51

11=x y=3

11) 49+3x=7x-23 3x=11y-1

7 0

3 years ago

Find three consecutive odd integers such that 10 times the first, plus 10 times the second, equals 10 more than 10 times the thi

SIZIF [17.4K]

Answer:

4

Step-by-step explanation:

If x is the third number, then x−1 and x−2 are the second and first numbers.

10(x−2) + 10(x−1) = 10 + 10x

x − 2 + x − 1 = 1 + x

2x − 3 = 1 + x

x = 4

8 0

3 years ago