+3 . I think, hope this helps
Solution :
a). The probability that the student will
the 1st question after the 4th attempt.
P (correct in the 4th attempt)
= ![$(1-0.75)^3 \times 0.75$](https://tex.z-dn.net/?f=%24%281-0.75%29%5E3%20%5Ctimes%200.75%24)
= 0.01171875
b). The probability that the student will
3 questions after 10 total attempts.
P( X = 3) for X = B in (n = 10, p = 0.75)
= ![$C(10,30) \times 0.75^3 \times 0.25^7$](https://tex.z-dn.net/?f=%24C%2810%2C30%29%20%5Ctimes%200.75%5E3%20%5Ctimes%200.25%5E7%24)
= 0.0031
c). The mean and the standard deviation for the number of attempts up to when the students gets all the questions correct is :
There are = 6 success, p = 0.75.
Therefore, this is a case of a negative binomial distribution.
![$E(X)=\frac{k}{p}$](https://tex.z-dn.net/?f=%24E%28X%29%3D%5Cfrac%7Bk%7D%7Bp%7D%24)
![$=\frac{6}{0.75}$](https://tex.z-dn.net/?f=%24%3D%5Cfrac%7B6%7D%7B0.75%7D%24)
= 8
So, ![$\sigma = \frac{\sqrt{k(1-p)}}{p}$](https://tex.z-dn.net/?f=%24%5Csigma%20%3D%20%5Cfrac%7B%5Csqrt%7Bk%281-p%29%7D%7D%7Bp%7D%24)
![$\sigma = \frac{\sqrt{6(1-0.75)}}{0.75}$](https://tex.z-dn.net/?f=%24%5Csigma%20%3D%20%5Cfrac%7B%5Csqrt%7B6%281-0.75%29%7D%7D%7B0.75%7D%24)
= 1.6330
I was wrong the answer is A I just realized that
This question belongs to simple algebric equation, where we need to add or subtract fractions by finding a common denominator.
Given total hours = 120
Number of hours tutored for 1st week =2 1/3 hours = 7/3 hours
Number of hours in the 2nd week = 3/2 = 1.5 hours
Let the number of more hours she needs to teach be x
![\frac{7}{3} + \frac{3}{2} + x = 20](https://tex.z-dn.net/?f=%5Cfrac%7B7%7D%7B3%7D%20%2B%20%5Cfrac%7B3%7D%7B2%7D%20%2B%20x%20%3D%2020)
= ![\frac{14+9+6x}{6}= 20}](https://tex.z-dn.net/?f=%5Cfrac%7B14%2B9%2B6x%7D%7B6%7D%3D%2020%7D)
23 + 6x = 120
6x = 97
x = 16.167
Hence Kiara needs 16.167 more hours.
And this belongs to a part-whole problem, because the time she still needs to tutor is unknown.
Answer:
1/3 or 0.3 (recurring)
Step-by-step explanation:
Let's substitute our numbers into the equation.
27 = 9x + 24 I multipled 8 by 3 in order to get 24, because x equals 3.
Now take away 24 leaving 9x on its own.
3 = 9x
Divide 9 to separate it from x.
3/9 = x
Simplify the fraction.
1/3 = x