SOLUTION: All the page numbers of a book are added beginning at page one. However, one page number was mistakenly added twice. The sum obtained was 1000. Which page number was added twice? D
Algebra.Com
Question 889429: All the page numbers of a book are added beginning at page one. However, one page number was mistakenly added twice. The sum obtained was 1000. Which page number was added twice? Do it in details.
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
s = ½(2a + (n-1)d)n
a=1
d=1
1000> 1/2*(2 + (n-1))*n
highest n=44
s = ½(2 + (43))44
s = 45*22
s=990
1000-990=10
10 was repeated twice
RELATED QUESTIONS
Dada opened a book randomly and began adding every seventh page number beginning with the (answered by checkley71,Adam)
The numbers 1,6,11,16... are written in order in a book, 50 to a page, beginning on page... (answered by math_helper)
One page is missing from a book(that page has two sides,so 2 page numbers).Now the sum of (answered by Edwin McCravy)
Some pages were torn out of a book by mistake. The person repairing the book noticed that (answered by KMST)
A book is opened to a page at random. The product of the facing page numbers is 3422 .... (answered by greenestamps,Alan3354)
The sum of the page numbers on the facing pages of a book is 573. What are the page... (answered by Ultimatemagic)
The sum of the page numbers on the facing pages of a book is 629. what are the page... (answered by Alan3354)
The sum of the page numbers on the facing pages of a book is 281. What are the page... (answered by stanbon)
The sum of the page numbers on the facing pages of a book is 295. What are the page... (answered by Alan3354)