The third one because its the only one decreasing
Answer:

Step-by-step explanation:
1) 4(2a+p)=c+p+a
2) Expand: 8a+4p=c+p+a
3) subract a and 4p: 7a=c-3p
4) Divide: a=
Answer:
Yes, the probability distribution is valid.
Step-by-step explanation:
Given :
Income range ___ midpoint(x) ___ %
5 - 15 __________ 10 _____20%
15 - 25 _________ 20 _____13%
25- 35 _________ 30 _____ 21%
35 - 45 _________40 _____ 17%
45 - 55_________ 40 ____ 20%
55 or more _______ 50 _____9%
Yes, we do have a valid probability distributuon ; as the summation of the percentage values is equal to 100%