frustrated with his consistent low scores in maths,Pradip tore off a certain number of consecutive leaves from his maths book.Each leaf is numbered on either sides and is considered to be two pages.If the sum of the page numbers which he tore off was 720,then how many pages did Pradip tear off from the book??POor Pradip

1) 16
2) 32
3) 42
4) 45

• Lets "n" be the pages pradip tear off from the book
  pradip tore off pages consecutive means pages that tore off are in A.P
  a , a+d , a+2d .............n
  Sum = n/2 * [2a + (n-1)*d]
  due to consecutive , d = 1
  So, by putting n= 32
  we get
  a = 7 .............(a positive & integer term )
  satisfy the question
  ANS = 32
  
  by putting n= 16
  a = 37.5 ......(not possible)
  
  by putting n = 45
  a = - ve terms .......(again not possible)
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