Answer: 35.675
Step-by-step explanation:
10.465−(−25.21)
The opposite of −25.21 is 25.21.
10.465+25.21
Add 10.465 and 25.21 to get 35.675.
35.675
Answer:
This problem is incomplete, we do not know the fraction of the students that have a dog and also have a cat. Suppose we write the problem as:
"In Mrs.Hu's classroom, 4/5 of the students have a dog as a pet. X of the students who have a dog as a pet also have cat as a pet. If there are 45 students in her class, how many have both a dog and a cat as pets?"
Where X must be a positive number smaller than one, now we can solve it:
we know that in the class we have 45 students, and 4/5 of those students have dogs, so the number of students that have a dog as a pet is:
N = 45*(4/5) = 36
And we know that X of those 36 students also have a cat, so the number of students that have a dog and a cat is:
M = 36*X
now, we do not have, suppose that the value of X is 1/2 ("1/2 of the students who have a dog also have a cat")
M = 36*(1/2) = 18
So you can replace the value of X in the equation and find the number of students that have a dog and a cat as pets.
Answer:
Option D is correct
Step-by-step explanation:
From the question, we have:



Required
The tree diagram
The selection process is as follows:

-- i.e. we write sack 2 as a subset of 1
-- i.e. we write sack 3 as a subset of 2
<em>The only tree diagram that illustrates this is: option D</em>