Question

HELLO FRIENDS PLEASE HELP
EXAM NEXT DAY OF MATHS ,AM REALLY WEAK IN MATHS ...

Find the sum :- 1+3+5+7+9..........149

Answer 1

here,
let no. of terms = n
first term (a)= 1

common difference (d) = 3 - 1 = 2

last term (l) = 149
L = a + (n - 1)d
149 = 1 + 2n - 2
150 = 2n

n = 75
therefore,
the sum...
sum = n/2(a + L)
= 75/2(150)
= 75*75
= 5625 ans
please mark me as brain list

Answer 2

the first term of this ap (a)=1. the common difference of this ap (d)=3-1=2. the last term of this ap. (l) =149. as we know that. l=a+(n-1) d 149=1+(n-1)2. 149-1÷2 =(n-1). 74+1=n. n=75. now using the formula to find the sum. Sn=n/2(2a+(n-1)d. Sn = 75/2(2×1+(75-1)×2. Sn=75/2(2+158). Sn=75/2(160). =75×80=6000. it is the sum of this ap. hope this is helpful