Question

En la primera fase del proceso selectivo para Al cuerpo de profesores eliminan a cuatro novenos De los aspirantes mientras que en la segunda fase eliminan A 5/7 de los que superaron la primera fase Si se presentaron 315 aspirantes cuál es la fracción De los aspirantes que han superado las dos fases Del proceso selectivo?

Answer 1

The fraction of the applicants who have passed the two phases of the selection process is
`(10)/(63)`.

Explanation:

The question is:

In the first phase of the selection process for the body of teachers they eliminate four-ninth of the applicants while in the second phase they eliminate 5/7 of those who passed the first phase. If there were 315 applicants what is the fraction of the applicants who have passed the two phases of the selection process?

The total number of applicants is

N = 315.

It is provided that 4/9th of the applicants were eliminated in the first phase.

Then the fraction of candidates who passed the first phase is:

Fraction who passed phase I =
`1-(4)/(9)=(5)/(9)`

Now, it is also provided that 5/7 of those who passed the first phase were eliminated in the second phase.

Then the fraction of candidates who passed the second phase is:

Fraction who passed phase II =
`1-(5)/(7)=(2)/(7)`

That is, 2/7 of the remaining applicants passed the second phase.

The fraction of the applicants who have passed the two phases is:

`(5)/(9)* (2)/(7)=(10)/(63)`

Thus, the fraction of the applicants who have passed the two phases of the selection process is
`(10)/(63)`.