Question

diksha read 10 pages of a storbook on 1st day. she read 15 pages of the same story book on the 2nd day, 20 pages on 3rd day and so on.

how many pages had the storybook, if diksha finished reading it on the eighth day?

Answer 1

the storybook had 220pages

Answer 2

on first day 10 pages
on 2nd day 15 pages
on 3rd day 20 pages
on 4 th day 25 pages
.
.
.
.on 8 th day 45 pages
now we have to find the total pages.....
by formula
S8 = n/2 ( first term + last term)
S8 = 8/2 ( 10 + 45 )
= 4(55)
= 220 pages is the answer . hope this helps dear.