BIG IDEAS MATH

Kevin has $1,427 in a savings account his brother Haley has saved in the mouth with a 4 that is 1/10 the value of the 4 in Kevin

Mekhanik [1.2K]

1/10 of 400 is 40
$1,427-40= $1387
so Haley's account has 1387 dollars or less

8 0

3 years ago

Read 2 more answers

Find the surface are of the regular pyramid

harina [27]

Answer:

146 $ft^{2}$

Step-by-step explanation:

9x6/2 = 27

27x4 = 108

6x6 = 36

36+108 = 146

6 0

2 years ago

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Two researchers conducted a study in which two groups of students were asked to answer 42 trivia questions from a board game. Th

Verizon [17]

Answer:

$(21.9-19.8) -1.966\sqrt{\frac{3.4^2}{200} +\frac{3.5^2}{200}}= 1.422$

$(21.9-19.8) -1.966 \sqrt{\frac{3.4^2}{200} +\frac{3.5^2}{200}}= 2.778$

And we are 95% confident that the true difference means are between $1.422 \leq \mu_1 -\mu_2 \leq 2.778$

Step-by-step explanation:

We know the following info:

$\bar X_1 = 21.9$ sample mean for group 1

$\bar X_2 = 19.8$ sample mean for group 2

$s_1 = 3.4$ sample standard deviation for group 1

$s_2 = 3.5$ sample standard deviation for group 2

$n_1 = 200$ sample size group 1

$n_2 = 200$ sample size group 2

We want to find a confidence interval for the difference of means and the correct formula to do this is:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2} \sqrt{\frac{s^2_1}{n_1} +\frac{s^2_2}{n_2}}$

Now we just need to find the critical value. The confidence level is 0.95 then the significance is $1-0.95 =0.05$ and $\alpha/2 =0.025$ . The degrees of freedom are given by:

$df= n_1 +n_2 -2= 200+200-2= 398$

The critical value for this case would be : $t_{\alpha/2}=1.966$

And replacing into the confidence interval formula we got:

$(21.9-19.8) -1.966\sqrt{\frac{3.4^2}{200} +\frac{3.5^2}{200}}= 1.422$

$(21.9-19.8) -1.966 \sqrt{\frac{3.4^2}{200} +\frac{3.5^2}{200}}= 2.778$

And we are 95% confident that the true difference means are between $1.422 \leq \mu_1 -\mu_2 \leq 2.778$

5 0

3 years ago

How to do you add probability

o-na [289]

To add the probabilities, you would have to treat them like any other numbers. If they are decimals or percents, you can follow basic addition rules. If you are given the probabilities as fractions, make sure that you have common denominators when you add them.

6 0

3 years ago

MANY PTS AND BRAINLY FAST

Troyanec [42]

Answer:

Option C

Step-by-step explanation:

we have

$-6x^{2} -6x+12=0$