Answer:
olk 69 -_-
Step-by-step explanation:
Sample size= n= 84
sample mean= x = 107 s
population standard deviation =σ= 11.7
As, population standard deviation is given so we use the estimate:
x(+/-) z(α/2)(σ/√n)
At 99% Confidence interval means significance level is α=1-0.99= 0.01
So,
α/2=0.005
Now, z at α/2=0.005
z= 2.576
Now, by putting values
107(+/-)((2.576)(11.7/√84))
( 107-((2.576)(11.7/√84)), 107+((2.576)(11.7/√84)) )
(103.7, 110.288)
Answer:
187/85 or in decimal form 2.2
Step-by-step explanation:
Make it a mixed fraction then find the common denominator
40 x 26.5 /2 is 530which is b
Answer:
2 mph
Step-by-step explanation:
time = distance / speed
Let c represent the rate of the current. Then the upstream rate of the boat relative to the shore is (5c -c) = 4c, and the <em>upstream time</em> is ...
... 12/(4c) = 3/c.
Likewise, the downstream rate is (5c +c) = 6c, and the <em>downstream time</em> is ...
... 12/(6c) = 2/c.
The <em>total time</em> is the sum of upstream and downstream times:
... 3/c +2/c = 2.5
... 5/c = 2.5 . . . . . . combine terms
... 5/2.5 = c = 2 . . . multiply by c/2.5
