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?

0 votes

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?

0 votes

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

...