C
given 1 /( 3 + √2 )
then rationalise the denominator by multiplying the numerator/ denominator by the conjugate of the denominator
the conjugate of 3 + √2 is 3 - √2
1 / (3 + √2 ) × (3 - √2 ) / (3 - √2 )
= (3 - √2 ) /( 9 - 2 ) = (3 - √2 ) / 7
Remmber
(a/b)/(c/d)=(a/b)(d/c)=(ad)/(bc)
conver to improper
4 and 1/5=20/5+1/5=21/5
2 and 1/3=6/3+1/3=7/3
(21/5)/(7/3)=(21/5)(3/7)=63/35=9/5=1 and 4/5
Corrected Question
The volume of air inside a rubber ball with radius r can be found using the function V(r) = four-thirds pi r cubed. What does V(5/7) represent?
Answer:
(B)the volume of the rubber ball when the radius equals five-sevenths feet
Step-by-step explanation:
The Volume of a sphere of radius r can be found using the formula:
Therefore comparing the expression: 
with V(r):
Thus, is the volume of a ball of radius 
feet.
The correct option is B.
Answer:
The probability that the next failure will not occur before 30 months have elapsed is 0.0454
Step-by-step explanation:
Using Poisson distribution where
t= number of units of time
x= number of occurrences in t units of time
λ= average number of occurrences per unit of time
P(x;λt) = e raise to power (-λt) multiplied by λtˣ divided by x!
here λt = 25
x= 30
P(x= 30) = 25³⁰e⁻²⁵/ 30!
P (x= 30) = 8.67 E41 * 1.3887 E-11/30! (where E= exponent)
P (x=30) = 1.204 E31/30!
Solving it with a statistical calculator would give
P (x=30) = 0.0454
The probability that the next failure will not occur before 30 months have elapsed is 0.0454
Answer:
D
Step-by-step explanation:
