48 is the answer you will get
We have
Mean, μ = 25 minutes
Standard Deviation, σ = 6.1
X = 30 minutes
The probability we are looking for is shown in the first diagram; it's the area on the right of X=30
We need to standardized the value X=30 using the formula


rounded to two dp
The z-table is shown on the second diagram only gives the probability when P(Z<z), so to work out the probability when P(Z>z), we do 1-P(Z<z)
P(Z>0.82) = 1 - P(Z<z) = 1 - 0.7939 = 0.2061
Answer:
4. .88
5. 17/9
6. 67/12
7. 47/56
8. 209/45 or 4 29/45, 4.64
9. 143/30
Step-by-step explanation:
Answer:
B
Step-by-step explanation:
y = (x + 1)/x
xy = x + 1
xy - x = 1
x(y - 1) = 1
x = 1/(y - 1)
Interswitch variables
f^-1(x) = 1/(x - 1)