A middle school has 200 boys and 300 girls enrolled in the seventh-grade. The principal randomly selects 45 seventh-grade students to take a lunch survey. How many of the seventh-grade students selected for the survey should the principal expect to be boys?

18

Step-by-step explanation:

Given

The school has 200 boys and 300 girls

The ratio of boys and girls is 2:3

If 45 seventh grade students are selected then the ratio of boys and girls remain the same

suppose there are 2x boys and 3x girls, such that ratio is 2:3

No of the boys are

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this

f

step-by-step explanation:

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