A vaccine, which is currently in use, is known to be 80% effective. A pharmaceutical company has developed a newvaccine and the company claims that 90% of the people given the new vaccine will develop the immunity. Supposethe claim of the company is true, and the newly developed vaccine is given to 20 people. The expected number of people in the sample that will develop the immunity is: a) 90% b) 18% c) 16% d) 80%

The correct answer is B) 18%

Step-by-step explanation:

Note that the vaccine is already and is 80% effective. This means that if the entire population was administered with the vaccine, only 8/10 would gain immunity leaving 2/10 or 0.2 exposed.

If the new vaccine, therefore, is supposed to be 90% effective, it is only pragmatic to administer it against those who do not have immunity which is 0.2 of the existing population.

So to get the percentage that will develop immunity, we have:

0.2 x 0.9 = 0.18 or 18%

Cheers!

x=-2

infinite number of lines, so there is an infinite number of equations.

step-by-step explanation:

there are an infinite number of line that passes through the point (-2,5)

x=-2   is one line that passes through the point

y = 5 is another line that passes through the point

(these two lines are perpendicular to each other).

since the number of   numbers are infinite and the slope is the ratio of two numbers,(change in y over change in x) we can have an infinite number of slopes.     our only condition is that it passes through the point (-2,5)

c. 27 units.

step-by-step explanation:

we are told that in circle a, ∠bae ≅ ∠dae.

we can see from our given diagram that in and ;

, as these are radii of our given circle.

therefore, by sas congruence postulate.

hence, side be will be equal to side de as corresponding parts of congruent triangles are congruent. so we can set an equation to find the value of x as:

now let us substitute x=17 in the expression for the length of be.

therefore, length of be will be 27 units and option c is the correct choice.