Question

Now let's find the sum of these 75 numbers
1 + 3 + 5 +...+ 149.
a= 1 and d = 2, n = 75
n
п
Method I S =
Sn = 2 [2a+(n-1)d]
Method II Sn =
S =
=
ż [t+t]
S = (1 +149)
S = Ox
S =
Х
n
S =
S =
n
n​

Answer 1

Answer:

please write full question

Answer 2

Answer:

A.P = 1+3+5+.......+149

Here,a=1,d=2,n=75

Sn=n/2[2a+(n-1)d]

S75=75/2[2*1+(75-1)2]

=75/2[2+74*2]

=75/2[2+148]

= 75/2[ 150]

=5625

So,the sum of 75 numbers of this A.P is 5625