The correct answer is d15
Answer:
34.87% probability that all 5 have a wireless device
Step-by-step explanation:
For each student, there are only two possible outcomes. Either they own a wireless device, or they do not. The probability of a student owning a wireless device is independent from other students. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
81% of students own a wireless device.
This means that 
If 5 students are selected at random, what is the probability that all 5 have a wireless device?
This is P(X = 5) when n = 5. So


34.87% probability that all 5 have a wireless device
Standard form of an exponential function is y=ab^x
when x=0, y=3, 3=ab^0, so you can figure out that a=3
when x=-1, y=6, 6=3b^(-1), b^(-1)=2, b=1/2
so the equation is y=3(1/2)^x
[4.6+2×(5_2)]÷2=7
4.6+2=4.8
4.8×5=240
240_2=238
238÷2=116
23; 20+4+9+ 28
he can estimate by rounding the numbers
24;19.99+4.19+8.50+27.75=
24.18+ 8.25+28=
24.18+36.25=
$60.43