Answer:
257 is prime.
Step-by-step explanation:
To evaluate if a number is prime, we just need to evaluate it for the prime numbers that are equal or lesser than the said number's square root.
In this case, √257 = 16.03 so we just need to see if 257 is divisible by <u>2, 3, 5, 7, 11 and 13</u> (the prime numbers that come before 16)
- 257 is odd, so it is not divisible by 2.
- The sum of its digits is 14, therefore, it is not divisible by 3.
- 257 ends in 7, therefore it's not divisible by 5.
- 257/ 7 = 36.71 so it's not divisible by 7.
- 257/ 11 = 23.36 so it's not divisible by 11
- Finally 257 / 13= 19.76 so it's not divisible by 13.
Therefore, 257 is prime.
I'm going to assume that you are trying to find the two numbers. Based on the information in the problem, we can create the following equations (where
and
are the two numbers):


We have a systems of equations. In this case, it would be easier to use elimination by adding vertically. This produces the result:


To find
, substitute the value for
into one of the earlier equations:


The two numbers are 12 and 18.
Answer:
Probability that a randomly selected woman's gestation period will be between 261 and 279 days is 0.68.
Step-by-step explanation:
We are given that the average human gestation period is 270 days with a standard deviation of 9 days. The period is normally distributed.
Firstly, Let X = women's gestation period
The z score probability distribution for is given by;
Z =
~ N(0,1)
where,
= average gestation period = 270 days
= standard deviation = 9 days
Probability that a randomly selected woman's gestation period will be between 261 and 279 days is given by = P(261 < X < 279) = P(X < 279) - P(X
261)
P(X < 279) = P(
<
) = P(Z < 1) = 0.84134
P(X
261) = P(
) = P(Z
-1) = 1 - P(Z < 1)
= 1 - 0.84134 = 0.15866
<em>Therefore, P(261 < X < 279) = 0.84134 - 0.15866 = 0.68</em>
Hence, probability that a randomly selected woman's gestation period will be between 261 and 279 days is 0.68.
Answer:
-4/8
Step-by-step explanation:
that's what my math says
Answer:
the answer is b
Step-by-step explanation: