Answer:
a) the probability that the minimum of the three is between 75 and 90 is 0.00072
b) the probability that the second smallest of the three is between 75 and 90 is 0.396
Step-by-step explanation:
Given that;
fx(x) = { 1/5 ; 50 < x < 100
0, otherwise}
Fx(x) = { x-50 / 50 ; 50 < x < 100
1 ; x > 100
a)
n = 3
F(1) (x) = nf(x) ( 1-F(x)^n-1
= 3 × 1/50 ( 1 - ((x-50)/50)²
= 3/50 (( 100 - x)/50)²
=3/50³ ( 100 - x)²
Therefore P ( 75 < (x) < 90) = ⁹⁰∫₇₅ 3/50³ ( 100 - x)² dx
= 3/50³ [ -2 (100 - x ]₇₅⁹⁰
= (3 ( -20 + 50)) / 50₃
= 9 / 12500 = 0.00072
b)
f(k) (x) = nf(x) ( ⁿ⁻¹_k₋ ₁) ( F(x) )^k-1 ; ( 1 - F(x) )^n-k
Now for n = 3, k = 2
f(2) (x) = 3f(x) × 2 × (x-50 / 50) ( 1 - (x-50 / 50))
= 6 × 1/50 × ( x-50 / 50) ( 100-x / 50)
= 6/50³ ( 150x - x² - 5000 )
therefore
P( 75 < x2 < 90 ) = 6/50³ ⁹⁰∫₇₅ ( 150x - x² - 5000 ) dx
= 99 / 250 = 0.396
-18/3
18/(-3)
<h2>
Explanation:</h2>
The complete question is as follows:
________________________________________________
Which expression best estimates -18 1/4 divided by 2 2/3?
18/3
-18/3
-18/(-3)
18/(-3)
________________________________________________
So in this exercise, we have two mixed fractions. This type of fractions comes from the combination of a whole number and a proper fraction fraction (numerator less than denominator). In order to solve this problem, we need to transform these mixed fractions into improper fractions (numerator greater than denominator). So:


By dividing:

<em>So the expressions that best estimates -18 1/4 divided by 2 2/3 are:</em>
<em>-18/3
</em>
<em>18/(-3)</em>
<em>Whose value in decimal form is -6.0</em>
<h2 /><h2>Learn more:</h2>
Estimate the distance between cities: brainly.com/question/12062666
#LearnWithBrainly
<u> P = 2(L +W)</u>
Divide each side of the equation by 2 : P/2 = L + W
Subtract W from each side : <em> P/2 - W = L</em>
I believe it is 64 miles.
Hope this helps! :)
4744 feet. work below. please mark brainliest.