Answer:
c. 
Step-by-step explanation:
Given,
Number of bacterias who alive for at least 30 days = 5,
Bacterias who alive for 2 days = 10,
Died bacterias = 10,
Total bacterias = 5 + 10 + 10 = 25,
Ways of choosing a bacteria =
=
= 25,
While, ways of choosing of a bacteria who will live after 1 week =
=
= 5,
Hence, the probability it will still be alive after one week =
= 
OPTION C is correct.
Let the price of 1 shirt be represented by = s
A pair of pants costs twice as much as a shirt, then the cost of pants is = 2s
The total cost of 1 pair of pants and 1 shirt is $18 , means : 
Solving this we get,


So, the price of 1 shirt is $6 and price of 1 pair of pants is = 2s = 2*6 = $12.
Answer:
The proportion of student heights that are between 94.5 and 115.5 is 86.64%
Step-by-step explanation:
We have a mean
and a standard deviation
. For a value x we compute the z-score as
, so, for x = 94.5 the z-score is (94.5-105)/7 = -1.5, and for x = 115.5 the z-score is (115.5-105)/7 = 1.5. We are looking for P(-1.5 < z < 1.5) = P(z < 1.5) - P(z < -1.5) = 0.9332 - 0.0668 = 0.8664. Therefore, the proportion of student heights that are between 94.5 and 115.5 is 86.64%
Answer: 2000
Step-by-step explanation:
55 multiplied by 20
is equal to 1,100
100 multiplied by 20
is equal to 2000
2000 ppl were surveyed