1still no answer........??
A book contains pages numbered from 1 to 50. 4 leaves (i. e., 8 pages) were torn off the book. What is the probability that the sum of the page numbers is 68?
-
UP 0 DOWN 0 0 5
5 Answers
1i`m not sure at all....is the answer 2/91??[assuming pg nos. 1 and 2 occur together in one leaflet and so on.]
1zero is the only possible answer the sum of all the pg no. is 1275 now even if we tear the last 8 pages, the sum cannot be 68
1use the fact that rth page has (2r-1,2r) so if rth page is torn off the sum is 4r-1
=> (4r-1) + (4s-1) + (4t-1) + (4u-1) = 68
=> r+s+t+u = 18..