Mary has 3 times books as many as martha, together they have 48, how much books thats mary have?

Martha has 1 time.

Mary has 3 times.

Both girls together have (1 + 3) = 4 times

4 times = 48 books.

1 time = 48/4 = 12 books.

Martha has (12 x 1) = 12 books.

Mary has (12 x 3) = 36 books.

1:3 is the ratio; Mary having a ratio of 1 and Martha a ratio of 3. Due to this, you divide 48 by 4 and you get how many books Mary has - 12. To prove this you multiply the number you get, 12, by 3 and you get 36. 36 is the number of books Martha has which is 3 times the number of books Mary has. Therefore, if you add both numbers together you should get 48 which is the total number of books.

12+36=48