All categories

3 years ago

Evaluate the expression: 28 + 87 = 3 x 23

Mathematics

1 answer:

TEA [102]3 years ago

8 0

Answer:

I think it's 202

Step-by-step explanation:

28+87 =115

3×2³

2×3=6

28+87=3×2³= 202

You might be interested in

Find the sum of the first 7 terms of the following series, to the nearest integer. 150,60,24...

Sonja [21]

A geometric series is the collection of an unlimited number of terms with a fixed ratio between them. The sum of the first seven terms of the series is 249.

<h3>What is geometrical series?</h3>

A geometric series is the collection of an unlimited number of terms with a fixed ratio between them.

The given series is an geometric series, the details of the series are:

a₁ = 150

r = 60/150 = 0.4

n = 7

The sum of the geometric series is,

S = 150(1-0.4⁶)/(1-0.4)

S = 248.976 ≈ 249

Hence, the sum of the first seven terms of the series is 249.

Learn more about Geometrical Series:

brainly.com/question/4617980

#SPJ1

4 0

2 years ago

Read 2 more answers

If i= the square root of -1 what is the value of i^3

BARSIC [14]

i =√-1

i^2 = -1

i^3

= i^2 * i

= -1√-1

= - √-1

5 0

3 years ago

The quality control manager of a chemical company randomly sampled twenty 100-pound bags of fertilizer to estimate the variance

lisabon 2012 [21]

Answer:

The 95% confidence interval for the variance in the pounds of impurities would be $3.829 \leq \sigma^2 \leq 14.121$ .

Step-by-step explanation:

1) Data given and notation

$s^2 =6.62$ represent the sample variance

s=2.573 represent the sample standard deviation

$\bar x$ represent the sample mean

n=20 the sample size

Confidence=95% or 0.95

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case the sample variance is given and for the sample deviation is just the square root of the sample variance.

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=20-1=19$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical values.

The excel commands would be: "=CHISQ.INV(0.025,19)" "=CHISQ.INV(0.975,19)". so for this case the critical values are:

$\chi^2_{\alpha/2}=32.852$

$\chi^2_{1- \alpha/2}=8.907$

And replacing into the formula for the interval we got:

$\frac{(19)(6.62)}{32.852} \leq \sigma^2 \frac{(19)(6.62)}{8.907}$

$3.829 \leq \sigma^2 \leq 14.121$

So the 95% confidence interval for the variance in the pounds of impurities would be $3.829 \leq \sigma^2 \leq 14.121$ .

4 0

3 years ago

Find all solutions in the interval [0, 2π) sin2x + sin x = 0

Molodets [167]

Sin 2 x + sin x = 0
( sin 2 x = 2 sin x cos x )
2 sin x cos x + sin x = 0
sin x ( 2 cos x + 1 ) = 0
sin x = 0
x 1 = 0
x 2 = π
or: 2 cos x + 1 = 0
2 cos x = - 1
cos x = -1/2
x 3 = 2π/3
x 4 = 4π/3

3 0

3 years ago

Can someone help? Math really, really sucks.

AveGali [126]

Please refer to the attachment for the answer and explanation. Hope it helps!!

4 0

2 years ago