If Jacob owns 12 books, how many different ways can he arrange 3 of these books on a single bookshelf

1320

Step-by-step explanation:

We will think as follows. Recall that at first, he chooses 3 books. Then, we want to see in how many ways he can arrange this books. For the first book, he has 3 options, for the second one 2 and for the third 1. Then, the total number of ways in which he can arrange 3 books is 3!. So we know that after choosing 3 books, he can arrange them in 3! ways. So, we want to check the total number of ways he can choose 3 books out of 12. That is given by the binomial coefficient . Then, the total number of ways of arranging 3 books is

Thus, he can arrange 3 books out of 12 in 1320 different ways

its the fourth option

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons