Answer:

Step-by-step explanation:
Since there are 20 students, this will be the denominator.
Now, to find how many students have a dog and a cat, you need to subtract all the numbers with 20. The leftover number will be the amount of students.
7+8+8=23
23-20=3
So, there are 3 students who have a dog and a cat.
So, the fraction will be 
Nick had 3 1/4 bottles before, and he had 1 2/4 bottles left, so that means
3 1/4 - 1 2/4 = 1.75
1.75= 1 3/4.
So, I do not agree with nick.
Hope this helps!!! :)
Answer:x = 7
Step-by-step explanation:
Similar figures have sides that are proportional. Setting up a proportion for the sides of the figures will help solve for 'x':
Cross-multiply: 3(x + 1) = 6(x - 3)
Distribute: 3x + 3 = 6x - 18
Combine like terms: 21 = 3x
Solve for 'x': x = 7