Using the mean concept, it is found that we will need 15 more points to bring up his average up to 90%.
The mean of a data-set is the <u>sum of all observations divided by the number of observations</u>.
In this problem:
- In the first 5 observations, total of 21 out of 25 points, hence the mean for these observations is
. - In the next n observations, mean of 1.
Hence, the mean is:

We want the mean to be of 0.9, thus:





3 more testes are need, each worth 5 points, hence, 15 more points are needed to bring up his average up to 90%.
A similar problem is given at brainly.com/question/25323941
Answer:
a. 205320
b. 34220
c. 60! / (35)! (25)! + 60!/ (40)!(20)! + 60!/ (45)! (15)!
Step-by-step explanation:
a) The number of ways to dustribute exams among the TA's is:
n / (n - r)!
n= number of things to choose from
r= Choosing r number
60P3= 60! / (60 - 3)!
(60)(59)(58)(57)! / (57)!
=205320
B) The number of ways to dustribute the exams among the TA's is:
n! /(n - r)! r!
60C3= 60! /(60 - 3)! 3!
= 60!/ 57! 3!
= 60 × 59 × 58 / 3 × 2 × 1
= 34220
C) The required number of ways is:
60C25 + 60C20 + 60C15
= 60! / (35)! (25)! + 60!/ (40)!(20)! + 60!/ (45)! (15)!
Answer:
D
Step-by-step explanation:
Answer:
500215
Step-by-step explanation:
1 liter contains 1000000 millimeters. So, 1/2 liters equal 500000m. We are already most of the way there! After it rained, the problem says another 215 millimeters was added to the birdbath. Then, we write the problem as 500000 + 215. And 500000+215 equals 500215. A total of 500215 millimeters of water was in the birdbath after it rained.
Hope this helps!