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3 years ago

What percent of 90 is 50

1 answer:

4 0

To re-phrase this: 50 is a certain percent of 90.

this can be written mathematically as 50=x%*90

let's divide both sides by 10:

5=x%*9

and divide both sides by 9:

$\frac{5}{9} =x%$

which in decimals is approximately 0.56 (but not exactly).

so 0.56=x%

and the x then 56

so 50 is approximately 56% of 90:

exactly 56%of 90 is 50.4

You might be interested in

What is the equation of this line written in slope-intercept form?

miv72 [106K]

i think you had a problem in number B which it's suppose to be 1/2 so the correct answer is B

Step-by-step explanation:

6 0

2 years ago

Situation: a 25 gram sample of a substance that’s used for drug research has a K-value of 0.1205

Lelu [443]

The decay model is given as

$N=N_0e^{-Kt}$

The substance's half-life is the time it takes for the substance to decay to half its original amount. In other words, it's the time $t$ such that $N=\dfrac{N_0}2$ . Substituting into the model, you have

$\dfrac12=e^{-Kt}$

You can solve for $t$ now.

$\dfrac12=e^{-Kt}$
$\implies\ln\dfrac12=\ln e^{-Kt}$
$\implies-\ln2=-Kt\ln e$
$\implies\dfrac{\ln2}K=t\approx5.7523\text{ days}$

8 0

3 years ago

Is the graph increasing, decreasing, or constant?

djyliett [7]

Answer:

It is increasing.

Step-by-step explanation:

Given the graph of a straight line, there are several ways to find its equation.

Method 1: This method works only if the y intercept is visible.

Find any two points, (x1, y1) and (x2, y2), on the line and substitute their coordinates into the following formula to get m:

Get b from inspection of the y intercept of the graph.

Substitute the numbers that you have obtained for m and b into the equation y = m x + b.

Method 2: This method works even if the y intercept is not visible.

As in method 1, find any two points, (x1, y1) and (x2, y2), on the line and substitute their coordinates into the following formula to get m:

Substitute the number that you obtained for m into the equation y = m x + b. Also, take one of the points, say (x1, y1), and substitute its coordinates into the equation. This gives:

y1 = m x1 + b

It may not look like it, but this equation has only one variable, b, and you can easily solve for it.

Substitute the numbers that you have obtained for m and b into the equation y = m x + b.

Method 3: This method has the advantage that it uses only algebra, not geometry, and can be applied to any type of function, not just the straight line:

Find two points, (x1, y1) and (x2, y2), that are on the line. Take the first point, (x1, y1), and substitute it into the straight line equation, y = m x + b. This gives:

y1 = m x1 + b

Similarly, take the second point, (x2, y2), and substitute it into the straight line equation, y = m x + b. This gives:

y2 = m x2 + b

Together, these two equations constitute a system of two equations in the two unknowns, m and b. We can solve them for m and b using the elimination method. To be specific, if we subtract the first equation from the second, then b is eliminated and we get the equation:

y2 − y1 = m x2 − m x1,

which, when solved for m, gives the same equation as in the other two methods, namely:

Find b by back-substitution. To be specific, substitute the number that you obtained for m into one equation of the system of equations, say into y1 = m x1 + b. It may not look like it, but this equation has only one variable, b, and you can easily solve for it

7 0

3 years ago

From a sample with nequals24, the mean number of televisions per household is 4 with a standard deviation of 1 television. Usin

Otrada [13]

Answer:

At least 18 of the households have between 2 and 6 televisions.

Step-by-step explanation:

Chebyshev Theorem

The Chebyshev Theorem can also be applied to non-normal distribution. It states that:

At least 75% of the measures are within 2 standard deviations of the mean.

At least 89% of the measures are within 3 standard deviations of the mean.

An in general terms, the percentage of measures within k standard deviations of the mean is given by $100(1 - \frac{1}{k^{2}})$ .

In this question:

Mean = 4

Standard deviation = 1

Percentage of households that have between 2 and 6 televisions.

2 = 4 - 2*1

So 2 is two standard deviations below the mean

6 = 4 + 2*1

So 6 is two standard deviations above the mean

By Chebyshev's Theorem, at least 75% of the measures are within 2 standard deviations of the mean.

Out of 24

0.75*24 = 18

At least 18 of the households have between 2 and 6 televisions.

6 0

3 years ago

Determine whether the two lines are parallel, perpendicular or neither x-3y=6 y=3x+4

Anna [14]

Answer:

neither

Here's how you know:

first, i'll simplify it so both are in slope-intercept form (y = mx + b).

x-3y=6

-3y = 6 - x

y = (1/3)x - 2

y=3x+4 is already in slope-intercept form, yay :)

these lines are neither parallel nor perpendicular.

The equations of parallel lines have THE SAME SLOPES (y = mx + b --> m would be exactly the same).

In contrast, perpendicular lines have NEGATIVE RECIPROCAL SLOPES (y = mx + b --> m would be -1/m).

--> since the slopes of these match neither of these definitions, we know it must be neither.

6 0

4 years ago