49of students at a school are boys. If there are 2610 students at the school, how many are girls?

The number of hours, t, that bacteria spread 10-fold can be modeled by the equation B(t) = B0(10)2t. There are 25 bacteria prese

nordsb [41]

Answer: 1.67 hours.

Explanation:

1) Function that models the number of bacteria:

$B(t)=B_0(10)^{2t}$

2) Bo = 25, then the function is:

$B_0=25(10)^{2t}$

3) To know how many hours will elpase until the number of bactaria is 55,00, you equals B to 55,500 in the equation and solve for t, in this way:

i) start

$55000=25(10)^{2t)$

ii) division property

$2200=10^{2t}$

iii) antilogarithm property

$2t = log_{10}2200$

iv) division property

$t=\frac{log_{10}2200}{2}$

v) Due the operations:

t = 1.67 hours.

Note that the time is less than 2 hours. That sounds fine since after 1 hour there will be 10 times 25 (250 bacteria), and after 2 hours 100 times 25 (2500 bacteria).

3 0

3 years ago

CAN SOMEONE HELP (AND HELP ME UNDERSTAND)

Mama L [17]

Consider angle XZY in the attached figure. It is always 1/2 the measure of arc XY, no matter where Z may be located on the major arc XZY. This is true even when ZY is very short.

Now, consider what happens when Z falls on top of tangent point Y. The angle is still half the measure of arc XY, still 62°.

Selection C is appropriate.

_____
I apologize for any confusion caused by my choice of Z as the name of the point I added. Nothing in my explanation is intended to refer to the Z already shown in the unmodified figure.

5 0

3 years ago

A sample of size 45 will be drawn from a population with mean 53 and standard deviation 11. Use the TI-84 Plus calculator. (a) I

sukhopar [10]

Answer:

a) We have the standard deviation and the mean, so it is appropriate to use the normal distribution to find probabilities for x.

b) There is a 15.97% probability that x will be between 54 and 55.

c) The 47th percentile of x is $X = 52.877$ .

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by

$Z = \frac{X - \mu}{\sigma}$

After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X. Subtracting 1 by the pvalue, we This p-value is the probability that the value of the measure is greater than X.

A sample of size 45 will be drawn from a population with mean 53 and standard deviation 11.

This means that $\mu = 53$ .