Find the two Z-scores that separate the middle 73.72% on the Standard Normal Curve.

+1.12 and -1.12

Step-by-step explanation:

Let the two z scores be .

Since  the two Z-scores that separate the middle 73.72% on the Standard Normal Curve, this can be represented by the equation:

From the z table of the normal distribution, z₁ = 1.12. That is a z score of 1.12 gives 0.8686.

The two z scores are +1.12 and -1.12 = ± 1.12

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: