In this current scenario,
Probability of passing, p = 65% = 0.65
Then,
Probability of not passing, q = 1-p = 1-0.65 = 0.35
Part (a): When 15 people are tested
(i) Number of people expected to pass
This is 65% of the 15 people tested. That is,
Number of people expected to pass = 0.65*15 = 9.75. This is rounded downwards as upward rounding will violate the 65% criteria.
Therefore,
Number of people expected to pass = 9 people.
(ii) Probability that 11 people are expected to pass the test
p(x=11) = [15Cx]*p^x*q^(15-x) = [15C11]*0.65^11*0.35^(15-11) = 0.1792 ≈ 17.92%
Part (b): Teenager determined to pass the test no matter how many times
(i) Probability that he passes the test the third time
This means that he will fail the first and second time. That is,
Probability pf passing the third time = q*q*p = 0.35*0.35*0.65 = 0.079625 = 7.9625%
(ii) Number of trials it takes to pass
This is a case of mathematical expected, E, that it takes before first occurrence of success. Normally,
E = 1/p
Substituting;
E = 1/0.65 = 1.54 ≈ 2
Therefore, at least two trials will be required.
B is the correct answer !
Answer:
25 goat and 15 chicken
Step-by-step explanation:
Say the number of goats is G, then the number of chickens is 40 - G as there are 40 heads and each chicken and each goat has one head.
The number of feet is 130
So 2(40 - G) + 4G = 130
So 80 - 2G + 4G = 130
2G = 50
G = 25
25 goats and 15 chickens
Answer:
Dave worked 60 hours.
Step-by-step explanation:
Let's assume that Dave worked a total of 
hours.
Since Kate worked 5 hours less than Dave: 
And Sarah worked 10 more hours than Dave: 
Combined, the three siblings worked 185 hours.
Dave worked 60 hours,
Kate worked 55 hours and Sarah worked 70 hours.
To check:
55 + 60 + 70 = 185 hours
Answer:
C. -3 < x _<_ 2
Step-by-step explanation:
So, the number line shows that the mark on -3 is empty, showing that x CAN NOT be equal to -3. But, the mark on 2 is filled in, meaning x CAN be equal to 2, but not higher than 2.
