Answer:
D. 28
Step-by-step explanation:

Answer:
The answer is 1/9 ⇒ the second answer
Step-by-step explanation:
* In the exponential functions we have some rules
(1) b^(-m) = 1/(b^m) (for all nonzero real numbers b)
- If we have negative power we reciprocal the base
to get positive power
(2) (b^m)^n = b^(mn)
- If we have power over power we multiply them
* In our problem: 
- At first change 27 to b^n
∵ 27 = 3 × 3 × 3 = 3³
∴ 
* Lets use rule (2)
∴
⇒ 3 × -2/3 = -2
* Use rule (1)
∴
⇒ reciprocal the fraction to change the sig of the power
* The answer is 1/9
A:4*7=28. so there are 7 multiples upto 30. P(A)=7/30
B:26,27,28,29 i.e. 4 numbers satisfy the 2nd criteria. P(B)=4/30
P(A∩B)=1/30 (since 28 belongs to both A&B)
P(A∪B)= P(A)+P(B)-P(A∩B)= (7+4-1)/30= 1/3