A los doctores ________

Why is fertilization in flowering plants called double fertilization?

Police often set up sobriety check points roadblocks where drivers are asked a few brief questions to allow the officer to judge whether or not the person may have been drinking. If the officer does not suspect a problem, drivers are released to go on their way. Otherwise, drivers are detained for a Breathalyzer test that will determine whether or not they will be arrested. The police say that based on the brief initial stop, trained officers can make the right decision 80% of the time. Suppose the police operate a sobriety checkpoint after 9 P.M. on a Saturday night, a time when national traffic safety experts suspect that about 12% of drivers have been drinking. What's the probability that a driver who is detained has actually been drinking?

Fill in the blank. Phrases such as increased by and more than are used to indicate the operation of _____. Phrases such as decreased by and less than are used to indicate the operation of _____.

What is a solubility product constant? How are such constants determined?

A platinum catalytic reactor in an automobile is used to convert carbon monoxide to carbon dioxide in an oxidation reaction of the form $2 \mathrm{CO}+\mathrm{O}_{2} \rightarrow 2 \mathrm{CO}_{2}$. Species transfer between the catalytic surface and the exhaust gases may be assumed to occur by diffusion in a film of thickness L=10 mm. Consider an exhaust gas that has a pressure of 1.2 bars, a temperature of $500^{\circ} \mathrm{C}$, and a CO mole fraction of 0.0012. If the reaction rate constant of the catalyst is $k_{1}^{\prime \prime}=0.005 \mathrm{m} / \mathrm{s}$ and the diffusion coefficient of CO in the mixture is $10^{-4} \mathrm{m}^{2} / \mathrm{s}$, what is the molar concentration of CO at the catalytic surface? What is the rate of removal of CO per unit area of the catalyst? What is the removal rate if $k_{1}^{\prime \prime}$ is adjusted to render the process diffusion limited?

Explain why it is possible to draw more than two different rectangles with an area of 36 square units, but it is not possible to draw more than two different rectangles with an area of 15 square units. The sides of the rectangles are whole numbers.

Determine whether each sequence is arithmetic. If so, identify the common difference. 2, 3, 5, 8, ...

What were the goals of the Grange?

Different operations with the same rational numbers usually result in different answers. Illustrate some curious exceptions. Show that

$$\frac { 13 } { 4 } + \frac { 13 } { 9 } \text { and } \frac { 13 } { 4 } \times \frac { 13 } { 9 }$$

give the same answer.

Simplify.

$$\frac { 4 } { 9 } \div \frac { 2 } { 3 } - \frac { 1 } { 2 }$$

Nine-year-old Emily Rosa conducted this test: A professional touch therapist put both hands through a cardboard partition and Emily would use a coin toss to randomly select one of the hands. Emily would place her hand just above the hand of the therapist, who was then asked to identify the hand that Emily had selected. The touch therapists believed that they could sense the energy field and identify the hand that Emily had selected. The trial was repeated 280 times. Assuming that the touch therapists have no special powers and made random guesses, find the mean and standard deviation for the numbers of correct responses in groups of 280 trials.

Use the derivative f' to determine the x-coordinates of the local maxima and minima of f, and the intervals of increase and decrease. Sketch a possible graph of f (f is not unique). f'(x)=(x-1)(x+2)(x+4)

Sketch the given region of integration R and evaluate the integral over R using polar coordinates.

$$\iint _ { R } 2 x y d A ; R = \{ ( r , \theta ) : 1 \leq r \leq 3,0 \leq \theta \leq \pi / 2 \}$$