Answer:
The width is 20 ft and the length is 80 ft
Step-by-step explanation:
Area = l * w
l = w +60
SA = 1600 ft^2 ( which is the regular area) The surface area of the water is just what is on top which is length times width
1600 = l*w
Substitute in l = w+60
1600 = (w+60) *w
Distribute the w
1600 = w^2 +60w
Subtract 1600 from each side
1600-1600 = w^2 + 60w -1600
0 = w^2 + 60w -1600
Factor
0=(w-20) (w+80)
Using the zero product property
w-20=0 w+80 =0
w=20 or w=-80
The width cannot be negative so
w=20
Now we need to find the length
l = w+60
l = 60+20
l =80
Answer:
Step-by-step explanation:
Taking the value of <em>t</em> and puting this value into the first equation, we got
Answer: (-3,-6)
Step-by-step explanation:
Answer:
you want 4 correct and 16 incorrect
there are 20 questions
each question has four answers, so
P(right answer) = 1/4
P(wrong answer) = 3/4
----
Since you want 4 correct of 20 we have a combination of 20C4
This is a binomial problem where p = 1/4, q = 3/4 and we get
(20 "choose" 4)*(probability correct)^(number correct)*(probability incorrect)^(number incorrect)
putting numbers in we get
(20c4)*(1/4)^4*(3/4)^16
This gives us
~ .189685
Step-by-step explanation:
Answer:
1
Step-by-step explanation:
Given the question above :
The probability distribution :
X : ___ 1 ___ 2 ___ 3 ___ 4 ____ 5
P(x): _ 0.1 __ 0.1 __ 0.6 _ 0.1 __ 0.1
The Variance : Var(X) = (Σx²*p(x)) - μ²
μ = E(X) = Σ(X * p(x)) :
Σ(X * p(x)) = (1*0.1)+(2*0.1)+(3*0.6)+(4*0.1)+(5*0.1)
μ = 3
Var(X): [(1^2*0.1)+(2^2*0.1)+(3^2*0.6)+(4^2*0.1)+(5^2*0.1)] - 3²
= 10 - 9
= 1
Hence. Variance = 1
