Question

Find the sum of all even numbers between 2 and 160

Answer 1

Answer:

6480

Step-by-step explanation:

sum of even numbers = n(n+1)

even no.s from 2 to 160 are 80

since, 1 to 10 = 5

16*5=80

sum of even numbers = 80(80+1)

= 80(81)

= 6480

Answer 2

Answer:

Step-by-step explanation:

a=2
Tn=160

d=2 because they're asking for even numbers

n= ?

Tn = a+(n-1)d

160 = 2 + (n-1)2

160 = 2 + 2n - 2

160 = 2n

n = 80

now for the sum,

Sn = n/2 (a+l)

80/2 (2+160)

40(162)

= 6480