Answer:
a) 8*88*10⁻⁶ ( 0.00088 %)
b) 0.2137 (21.37%)
Step-by-step explanation:
if the test contains 25 questions and each questions is independent of the others, then the random variable X= answer "x" questions correctly , has a binomial probability distribution. Then
P(X=x)= n!/((n-x)!*x!)*p^x*(1-p)^(n-x)
where
n= total number of questions= 25
p= probability of getting a question right = 1/4
then
a) P(x=n) = p^n = (1/4)²⁵ = 8*88*10⁻⁶ ( 0.00088 %)
b) P(x<5)= F(5)
where F(x) is the cumulative binomial probability distribution- Then from tables
P(x<5)= F(5)= 0.2137 (21.37%)
Answer:
Step-by-step explanation:
A=3,500×(1+0.0485÷4)^(4×11)
A=5,947.99
6000=3500(1+0.0485/4)^4t
Solve for t to know the time needed to reach 6000
Time=11.2
So the time needed is 11 years and 2 months
Answer:
Fraction of the students in the 7th grade class carry a cell phone = 3/5
24 students carry a cell phone
Step-by-step explanation:
40 students in the 7th grade, 60% of the students carry a cell phone.
so 40 x 0.6 = 24 students carry a cell phone
24/40 = 3/5
