Answer:
7
Step-by-step explanation:
We want to find the number 4-digit of positive integers n such that removing the thousands digit divides the number by 9.
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Let the thousands digit be 'd'. Then we want to find the integer solutions to ...
n -1000d = n/9
n -n/9 = 1000d . . . . . . add 1000d -n/9
8n = 9000d . . . . . . . . multiply by 9
n = 1125d . . . . . . . . . divide by 8
The values of d that will give a suitable 4-digit value of n are 1 through 7.
When d=8, n is 9000. Removing the 9 gives 0, not 1000.
When d=9, n is 10125, not a 4-digit number.
There are 7 4-digit numbers such that removing the thousands digit gives 1/9 of the number.
No. It would be a arithmetic sequence
:-):-):-):-):-)
Step-by-step explanation:
1) 40÷10
2) 40÷2
Answer:
P(X=3) = 0.2013
Step-by-step explanation:
After taking and tagging the first 20 birds, then we have a proportion of 20% of tagged birds within the population, that is
Supposing that the probability (0.20) of capturing a bird <em>remains constant</em>, we may resolve it as it follows:
Capturing 10 birds can be considered as a binomial experiment with a success probability p = 0.2
Let, 
be the expression of the binomial distribution, for our case we have:
p=0.2
x = 3
n=10
Then,
Therefore, the probability that exactly 3 of the 10 birds in the new sample were previously tagged is 20.13%
