### Solution:

Concept- The average is a single number that represents a list of numbers. The average is the sum of the numbers divided by the number of averaged numbers. Here, the student bought a book at one store and a book at another. You need to multiply the number of books in the first and second stores by the price to calculate the total price. Then add the two and divide by the total number of books the student bought at the first and second stores.Students are Rs from a bookstore. 4 books at 120, Rs from another bookstore. It is assumed that you bought 6 books at 150. Therefore, in the first store, Number of books = 4 The price per book is = Rs.120 The total amount of books he bought at the first store is In the case of the second store Number of books = 6 The price per book is = Rs.150 The total amount of books he bought at the second store is Therefore, the total amount of books he bought from both stores is Total number of books purchased by students at the 1st and 2nd stores The average price he paid per book is obtained by dividing the total by the number of books. This is the average price Hence, the correct answer is option (1).