Evaluate the expression -4x+7 if x= -1

How many ML of a 35% acid mixture and a 95% acid mixture should be mixed to get 120 ML of a 40% acid mixture?

Anon25 [30]

ANSWER:

110ML of 35% acid solution must be mixed with 10ML of 95% solution to obtain 120ML of 40% solution.

SOLUTION:

First, set up table. fill in the unknowns with variables x and y. The table is attached below.

From the table shown below, we can easily set up the two equations.

Sum of values of two acids = Value of mixture

0.35x + 0.95y = 48

For convenience, we will multiply the entire equation by 100,

35 x + 95y = 4800 ------ (1)

Now, Sum of amounts of each acid = Amount of mixture

x + y = 120 --------- (2)

Multiply eqn 2 with 35 for easy calculation and derive the equation into one variable.

35 = 35x + 35y = 4200

Subtracting equation (2) from (1), we get

0 + 60y = 600

Thus, 60y = 600

$y = \frac{600}{60} = 10$

Substituting y = 10 in (2),

35x + 35(10) = 4200

35x + 350 = 4200

35x = 4200 - 350

35x = 3850

$x = \frac{3850}{35} = 110$

So, we have x = 110 and y = 10

We can conclude that 110ML of 35% acid solution must be mixed with 10ML of 95% solution to obtain 120 ML of 40% solution.

3 0

3 years ago

A rectangular computer table measures 30 inches by 50 inches. We need to cover it with square tiles. What is the side length of

jekas [21]

Answer:

a) 10*10 inch, b)yes, c) 15

Step-by-step explanation:

a)

we need to calculate the Greatest Common Factor between 30 and 50

$30 = 2 \times 3 \times 5 \\ 50 = 2 \times 5 \times 5 \\ GCM = 2 \times 5 = 10$

then, the square tiles will be 10 inch *10 inch

b) it will change because they don't need to have the largest slab possible so they will use any other comon factor with a size they consider correct for the cheese.

c)

$30 \div 10 = 3 \\ 50 \div 10 = 5 \\ 3 \times 5 = 15$

15 squares of 10inch*10inch of cheese could be cut.

6 0

3 years ago

Read 2 more answers

in a given year, the rate of flu infection for the general public was 8.3%. And sample of 200 people who receive the flu vaccine

makkiz [27]

Answer:

$\fbox{\begin{minipage}{10em}Option A is correct\end{minipage}}$

Step-by-step explanation:

Step 1: Define significance level

In this hypothesis testing problem, significance levels α is selected: $0.05$ , the associated z-value from Laplace table:

Φ( $z$ ) = α - $0.5 = 0.05 - 0.5 = -0.45$

=> $z$ = $-1.645$

Step 2: Define null hypothesis ( $H_{0}$ ) and alternative hypothesis ( $H_{1}$ )

$H_{0}$ : rate of flu infection $p$ = 8.3% or 8.3/100 = 0.083

$H_{1}$ : rate of flu infection $p$ < 8.3% or 8.3/100 = 0.083

Step 3: Apply the formula to check test statistic:

$K = \frac{f - p}{\sqrt{p(1 - p)} } * \sqrt{n}$

with $f$ is actual sampling percent, $p$ is rate of flu infection of $H_{0}$ , $n$ is number of samples.

The null hypothesis will be rejected if $K < z$

Step 4: Calculate the value of K and compare with $z$

$K = \frac{(\frac{3.5}{100}) - 0.083}{\sqrt{0.083(1 - 0.083)} } * \sqrt{200} = -2.46$

We have $-2.46 < -1.645$

=>This is good evidence to reject null hypothesis.

=> The actual rate is lower. (As $H_{1}$ states)

Hope this helps!

:)

5 0

3 years ago

The formula for the cost of buying a car=

svet-max [94.6K]

8000-2600=5400
5400/12=450
monthly pavement =450
12x450+2600=8000

5 0

3 years ago

There were 4289 fans at todays basketball game. Round 4289 to the nearest hundred

timama [110]

Answer:

4,300

Step-by-step explanation:

Is 289 closer to 300 or 200?

V

[300] [200]

Add the 4

= 4, 300

- I . A -

4 0

3 years ago