Question

Find the sum of the even integers between 30 and 70

Answer 1

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

Answer 2

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=(19)/(2) (32+68)`

`sum=950`.............Answer