Question

find the sum of the even integers between 30 and 70

Answer 1

we have to find sum of even integer between 30 and 70

first term is 32

$a_1=32$

$a_2=34$

......

$a_n=68$

common difference is

$d=2$

firstly , we will find n

we can use formula

$a_n=a_1+(n-1)d$

$68=32+(n-1)*2$

$n=19$

now, we can find sum

$sum=\frac{19}{2} (32+68)$

$sum=950$.............Answer

Answer 2

even numbers between 30 and 70 are:

32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68

sum = 32+34+36+38+40+42+44+46+48+50+52+54+56+58+60+62+64+66+68

sum =950