Question

How to solve this ? Please explain.

Answer 1

Tn=a+(n-1)×d

798 =707+(n-1)×7

798 =707+7n-7

798 =700+7n

98. = 7n

n= 14

Answer 2

1st of all we have to know that how many numbers are in 1 to 100 which are divisible by 7,
7×1=7
7×2=14
7×3=21
7×4=28
.
.
..
..
...
...
7×14=98.
98 is last number which is divisible by 7 in 1 to 100,so 14 numbers can be divisible by 7 in 100 consecutive numbers but in some cases like above first number is also divisible by given number
:.700,707,714,721,728,735,742,749,756,763,770,777,784,791 & 798 are the 15 numbers which are divisible by 7 in 700 to 800.

Hope it helps you !!!
Mark me as brainlilist.