Con las 5 primeras letras del alfabeto ¿ cuantas palabras de 3 letras puedo formar?

21/40.

Step-by-step explanation:

There are 3 geometry and 7 algebra books.

If the geometry book is drawn first probability = 3/10

If the second is algebra P = 7/9.

If the third is algebra P = 6/8 = 3/4.

So the probability  of all three being drawn in this order = 3/10 * 7/9 * 3/4

= 63/360

= 7/40.

Now there are a total of 3 ways in the order they are drawn, That is:

GAA

AGA

AAG.

So the required probability = 3 * 7/40

= 21/40.