Number of ways to select 3 books from 13 books for adoption is 286 .
<u>Step-by-step explanation:</u>
A Permutation is an ordered Combination. When the order does matter it is a Permutation. There are basically two types of permutation:
- Repetition is Allowed: such as the lock above. It could be "333".
- No Repetition: for example the first three people in a running race. You can't be first and second.
Formula is given by:
, where n is the number of things to choose from, and we choose r of them, no repetitions, order matters. Here , n=13 , r=3.
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
∴ Number of ways to select 3 books from 13 books for adoption is 286 .
To solve the problem, get the
percentage of each test by multiplying the score and the percentage then add it all up:
82 * .25 (highest test grade) + 65* .15 (lowest test grade) +
71*.20 (each test remaining) + 77*.20 (each test remaining) + 92*.20 (homework
grade)
= 20.5 + 9.75 + 14.2 + 15.4 + 18.4 = 78.25 or 78% in whole number
Answer:
66
Step-by-step explanation:
Use the formula for the mean of a set of numbers:
sum of the numbers
average = --------------------------------
count of numbers
Here we know that the average mark was 68, so we can write:
75 + 62 + 84 + 53 + x
average = 68 = ----------------------------------
5
or 274 + x
68 = -------------------
5
Solving for x, we multiply both sides by 5: 340 = 274 + x.
Subtracting 274 from both sides effectively isolates x:
340 = 274 + x
- 274 -274
------------------------
66 = x
The fifth student's mark was 66.
Answer:

Step-by-step explanation:
we would like to expand the following logarithmic expression:

remember the multiplication logarithmic indentity given by:

so our given expression should be

by exponent logarithmic property we acquire:

hence, our answer is A