Ms. Sharma asked her students to find the sum of all pages...............Find the page number which Sumit forgot to add?

Question

Ms. Sharma asked her students to find the sum of all pages of their maths book.
Sumit gave the answer as 1098.
Ms. Sharma told him that he has not added one page.
Find the page number which Sumit forgot to add?

Answer 1

Ans : Missing number is 30
As per Arthimetic Sequence formula
Sn=n/2{2a1+(n-1)d}
Where,
a1=1(first term)
d=1 (common difference)
n=46 (No of terms)

S46=1081
S47=1128
Sumit answer is between S46 & S47
So Difference between
Sumit answer and S47 value
1128-1098=30
Then
S46=1081
...........-30
..........+47

....... 1098