Find the sum of all integers between 84 and 719, which are multiples of 5

given an AP is required of all integers between 84 and 719, which are multiples of 5

To find: the sum of all integers between 84 and 719, which are multiples of 5

So, the sequence is 85, 90, 95….715

It is an AP whose first term is 85 and d is 5

Hence the sum is given by the formula

Now for the finding number of terms, the formula is

n = 127

Substituting n is the sum formula we get

s = 50800