Question

find the sum of 2+4+6+........+200 ​

Answer 1

a = 2

d = 4-2=2

last term = a+(n-1)d

200 = 2 +(n-1)2

198/2= n-1

99+1 = n

100 = n

So, 200 is the 100th term.

Sum of 100 terms = n/2(a+l)

=> 100/2(2+200)

=>50×202

=>10100

Cheers!✌