A national survey of companies included a question that asked whether the company had at least one bilingual telephone operator. The sample results of 90 companies follow (Y denotes that the company does have at least one bilingual operator; N denotes that it does not).

N N N N Y N Y N NY N N N Y Y N N NN N Y N Y N Y N YY Y N Y N N N Y NN Y N N N N N N NY N Y Y N N Y N YN N Y Y N N N N NY N N N N Y N N NY Y Y N N Y N N NN N N Y Y N N Y N
Use this information to estimate with 95% confidence the proportion of the population that does have at least one bilingual operator.

a

step-by-step explanation:

given the 2 equations

- x + y = - 2 → (1)

2x - 3y = 4 → (2)

multiplying (1) by 2 and adding to (2) will eliminate the x- term

- 2x + 2y = - 4 → (3)

add (2) and (3) term by term

(2x - 2x) + (- 3y + 2y) = (4 - 4), simplifying gives

- y = 0 ⇒ y = 0

substitute y = 0 in either of the 2 equations for corresponding value of x

substituting in (2) gives

2x = 4 ( divide both sides by 2 )

x = 2

solution is (2, 0 ) → a

in the simple case, the two triangles point x and y are congruent because every corresponding side has the same length, and every corresponding angle has the same measure.