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 .
Answer:
8 ft
Step-by-step explanation:
t = a + b/2 times 2
2 + 6 = 8
8/2 = 4
4 x 2 = 8
Answer:
170 children
74 students
85 adults
Step-by-step explanation:
Given
Let:
For the capacity, we have:
For the tickets sold, we have:
Half as many as adults are children implies that:
Required
Solve for A, C and S
The equations to solve are:
-- (1)
-- (2)
-- (3)
Make C the subject in (3)
Substitute in (1) and (2)
-- (1)
Make S the subject
-- (2)
Substitute
Solve for A
Recall that:
Recall that:
Hence, the result is:
So, the total number of balls is 11. We want to pick 2 red balls and 1 green ball. WLOG (since order doesnt matter here), we can say he picks red, green, red. That means on his first pick, he has a 
chance of picking the red ball, and he places it back in the bag. The probability of picking a green ball is 
, and then he places the ball back in the bag. The probability of picking the last red ball is the same as the last red ball example, and we simply multiply the probabilities together as per the multiplication rule to get:
Now, without replacement the order does matter. He picks a red ball, a red ball then a green ball. The probability of picking the first red ball is
, and the probability of picking the second red ball is 
and the probability of picking the green ball is
. We want to multiply thm again, as per the multiplication rule like the last problem.
0.3 is the decimal of 45/150
To change fraction into decimal you need the divide the denominator by the numerator.
So 150 divided by 45 is 0.3.
