Question

if 3,7,11...........till403 is an ap. find the sum of the terms

Answer 1

Answer:

Given data :

a=3

d =4

l=403

n=?

l=a+(n-1)d

403=3+(n-1)(4)

400=(n-1)(4)

400/4 =n-1

n=101

S=n/2(a+l)

S = 101/2(3+403) On solving, we get ;

S = 20503

Answer 2

Answer:

22523.

Step-by-step explanation:

given a=3,d=4.

403=a+(n-1)d

403=3+(n-1)4

403=3+4n-4

403=4n-1

404=4n

n=404÷4=101

n=101.

sum=n÷2(2a+(n-1)d))

sum=101÷2(6+(110×4))

sum=101÷2(6+440)

sum=101÷2×446

sum=101×223

sum=22523.