Answer:
a) a
b) ab
e) bbbbb
Step-by-step explanation:
We are given the following in the question:


a) a
It is given that 
b) ab

Thus, ab belongs to S.
c) aba
This does not belong to S because we cannot find x for which xb belongs to S.
d) aaab
This does not belong to S because we cannot find x for which xb belongs to S.
e) bbbbb

Thus, bbbbb belongs to S.
Both
1 times a=a
and
b times 0=0
I think it's true but I'm not 100% sure
Hot dogs are sold in packs of 10. 30 divided by 10 equals 3. (30/10=3)
Buns are sold in packs of 8. 30 divided by 8 equals 3.75. (30/8=3.75) but we must round to 4 since we can’t buy 75% of a pack of buns.
3 packs of hotdogs and 4 packs of buns