Answer:
A darts player practices throwing a dart at the bull’s eye on a dart board. Her probability of hitting the bull’s eye for each throw is 0.2.
(a) Find the probability that she is successful for the first time on the third throw:
The number F of unsuccessful throws till the first bull’s eye follows a geometric
distribution with probability of success q = 0.2 and probability of failure p = 0.8.
If the first bull’s eye is on the third throw, there must be two failures:
P(F = 2) = p
2
q = (0.8)2
(0.2) = 0.128.
(b) Find the probability that she will have at least three failures before her first
success.
We want the probability of F ≥ 3. This can be found in two ways:
P(F ≥ 3) = P(F = 3) + P(F = 4) + P(F = 5) + P(F = 6) + . . .
= p
3
q + p
4
q + p
5
q + p
6
q + . . . (geometric series with ratio p)
=
p
3
q
1 − p
=
(0.8)3
(0.2)
1 − 0.8
= (0.8)3 = 0.512.
Alternatively,
P(F ≥ 3) = 1 − (P(F = 0) + P(F = 1) + P(F = 2))
= 1 − (q + pq + p
2
q)
= 1 − (0.2)(1 + 0.8 + (0.8)2
)
= 1 − 0.488 = 0.512.
(c) How many throws on average will fail before she hits bull’s eye?
Since p = 0.8 and q = 0.2, the expected number of failures before the first success
is
E[F] = p
q
=
0.8
0.2
= 4.
8 x 12 = 96 sq ft
<span>4 x 8 = 32 sqft </span>
<span>96 / 32 = 3 panels </span>
<span>3 x 4 = 12 panels. I'm not sure which answer that would be. :-( If any, I would select C.) 6 panels. </span>
Answer:
Terminating decimals have a finite number of digits after the decimal point. Repeating decimals have one or more repeating numbers or sequences of numbers after the decimal point, which continue infinitely.
<h3>
Answer: choice B) 36</h3>
=================================================
Explanation:
The vertical sides, when read from left to right, can be divided to get this fraction: 9/90
Following the same order and direction, we divide the slanting corresponding sides to get: b/360
The fractions we constructed are equal to one another, as the triangles are said to be proportional.
We have the fraction 9/90 = b/360
Lets cross multiply and solve for b
--------------------
9/90 = b/360
9*360 = 90*b
3240 = 90b
90b = 3240
90b/90 = 3240/90
<h3>b = 36</h3>
--------------------
A quick way to do this may be to notice how the jump from 9 to 90 is "times 10" so the jump from b to 360 is also "times 10". Think in reverse to divide 360 over 10 and we land on 36 as our answer. This line of thinking does not work as simple for all proportional problems.