The answer is: 4.5 cups.
The explanation is shown below:
1. You need 3 cups of milk to make 30 biscuits.
2. Therefore, to solve the exercise you only need to multiply 45 biscuits by 3 cups and divide this by 30 biscuits.
3. Let's call the cups you will need to make 45 biscuits
. Then, you have:

4. Therefore, you will need 4.5 cups to make 45 biscuits.
9 and 12 are slope-intercept form and 10 and 11 are point-slope form
(33/7) / (1 13/14)
= (33/7)/ (27/14)
= (33/7)* (14/27)
= 22/9
= 2 4/9
The final answer is 2 4/9~
What happened in the first questions doesn't influence the final question, so the probability is simply 1/5 = 0.2