Question

Find the sum of first 123 even natural numbers.

The first n even natural numbers are: 2, 4, 6, 8, ...., 2n

They form an A.P. with a = _____, t = _____

∴ S = _____

=

n

2

[ 2 + 2n ]

=

n

2

× 2 [ 1 + n ]

= ____

Now S = 123 × _____

= 123 × 124

∴ S = _____

Thus, the sum of first 123 even natural numbers is _____​

Answer 1

Answer:

15252

Step-by-step explanation:

The even natural numbers are in AP :

2,4,6,8,10,.....................(123 no.)

here a=2,d=2 and n=123

Thus sum of first 123 even numbers

=123/2( 2*2+122*2)

=123/2*(248)

=123*124

=15,252