A maybe? I don’t know honestly
I need points so imma answer
Answer:
a. closed under addition and multiplication
b. not closed under addition but closed under multiplication.
c. not closed under addition and multiplication
d. closed under addition and multiplication
e. not closed under addition but closed under multiplication
Step-by-step explanation:
a.
Let A be a set of all integers divisible by 5.
Let
∈A such that 
Find 

So,
is divisible by 5.

So,
is divisible by 5.
Therefore, A is closed under addition and multiplication.
b.
Let A = { 2n +1 | n ∈ Z}
Let
∈A such that
where m, n ∈ Z.
Find 

So,
∉ A

So,
∈ A
Therefore, A is not closed under addition but A is closed under multiplication.
c.

Let
but
∉A
Also,
∉A
Therefore, A is not closed under addition and multiplication.
d.
Let A = { 17n: n∈Z}
Let
∈ A such that 
Find x + y and xy


So,
∈ A
Therefore, A is closed under addition and multiplication.
e.
Let A be the set of nonzero real numbers.
Let
∈ A such that 
Find x + y

So,
∈ A
Also, if x and y are two nonzero real numbers then xy is also a non-zero real number.
Therefore, A is not closed under addition but A is closed under multiplication.
Answer:
Step-by-step explanation:
3 sheets are shared between four friends.
Each friends will get = 3 ÷ 4
= 
Answer:
19.44
Step-by-step explanation:
We have the following information:
3 red balls, 5 green balls, and 1 yellow ball
In total there are 3 + 5 + 1 = 9 balls.
We calculate the probability of each:
Network: 3/9
Green: 5/9
Yellow: 1/9
Each one corresponds a price in profit or losses:
Network: 4
Green: -3
Yellow: 10
So in total it would be the sum of the multiplication of the probability and the price and then multiply everything by 25:
(4 * 3/9 + -3 * 5/9 + 10 * 1/9) * 25 = (0.777) * 25
= 19.44