Question

. There are 120 pages in a book. Then the sum of all odd and even number is

Answer 1

Answer:

Then the sum of all odd =1+O=1 and the even number is 2

Answer 2

Step-by-step explanation:

sum of an arithmetic series for the first n terms = [2a + (n-1) d] n /2

sum of the even page numbers :    see that there are 60 of them.

    2 + 4 + 6 + 8 + .... + 120

  = [ 2 * 2 + (60 - 1) 2] * 60/2 = 3660

sum of the odd page numbers:  (there are 120 - 60 = 60 numbers)

  = 1 + 3 + 5 + 7 + .... + 119

  =  [ 2 * 1 + (60 -1) 2 ] * 60/2  = 3600