Answer:
a. 0.38%
b. 266.75 days
Step-by-step explanation:
We have the following data, mean (m) 269 and standard deviation (sd) 15, therefore:
a. The first thing is to calculate the number z:
z (x) = (x - m) / sd
z (309) = (309-269) / 15 = 2.67
When looking in the normal distribution table (attached), we have that at this value of z, the probability is:
P (z> 2.67), that is to say we must look in the table -2.67 and this value corresponds to 0.0038, that is to say 0.38%
b. Find the z-value with a left tail of 44%, i.e. 0.44. We look in the table for this value and what value of z corresponds.
invNorm (0.44) = -0.15
Find the corresponding number of days:
x = z * sd + m
we replace
d = -0.15 * 15 + 269 = 266.75 days
X^2+3x=24, halve the linear coefficient, square it, and add it to both sides
In this case (3/2)^2=2.25
x^2+3x+2.25=26.25 now the left side is a perfect square...
(x+1.5)^2=26.25 take the square root of both sides
x+1.5=±√26.25 subtract 1.5 from both sides
x=-1.5±√26.25
x=-1.5-√26.25 and -1.5+√26.25
x≈ -6.62 and 3.62
Answer:
10:30 A.M
Step-by-step explanation: