Fernando has a prime number of books between 21 and 30 he says that if he takes 4of the books away he will be able to place the same number of books on wacho shelf of this bookcase how Many books does fernando have how many shelves are on the bookcase

29 books ; 5 bookshelfs

Step-by-step explanation:

Solving logically ;

Prime numbers between 21 and 30 = 23, 29

Hence, number of books Fernando has is either 23 or 29

Taking 4 away from the number of books, he'll be able to arrange same number of books on each of his book shelve;

From the statement, we can conclude that :

Subtracting 4 from the number of books Fernando has should give a perfect square

If 23 books

23 - 4 = 19 ; 19 isn't a perfect square

If 29 books :

29 - 4 = 25

Hence, to place the same Number of books on each shelf :

Sqrt(25) = 5

Hence, number of bookshelf = 5

4444444444444 i think

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads