Question

it is given that 2 + 4 + 6+...... + 200 X then find the value of x​

Answer 1

Answer:

x=10100

Explanation:

There are 100 numbers...so,

first number is 2

100th number is 200

so,sum(x)=(2+200)×100/2

x=202×100/2

x=20200/2

so,x=10100

Answer 2

Answer:

a = 2 , d = 4-2 = 2 , Sⁿ = 200

then we put this in Sⁿ formula....

Sⁿ = n/2 (2a + (n - 1) d)

200 = n/2( 2(2) + (n - 1) 2)

400 = n(4+(n-1) 2)

400 = n (4+ 2n - 2)

400 = n (2+2n)

400 = 2n + 2n²

2n² + 2n - 400 = 0

(taking 2 as common )

n² + n - 200 = 0

after finding the value of nth term

put the value in Sⁿ formula

Sⁿ = n( a + l)