Question

I NEED HELP ASAP!!!!!

Find the sum 21 + 25 + 29 + .....+ 253
A) 8,083
B) 7,946
C) 2,360
D) 7,493

Answer 1

Answer: 328

Step-by-step explanation: I don't know if you worded the question wrong or if I did something wrong, but that is the answer I got.

Answer 2

Answer:8083

Explanation:

21+25+.......+253 this is an AP

a=21 FIRST TERM

d=25-21=4 COMMON DIFFERENCE IS OBTAINED BY SUBTRACTING PREVIOUS TERM

WE WILL FIND FIRST NUMBER OF TERMS

an=a+(n-1)d

253=21+(n-1)(4)

253-21=(n-1)4

232 =(n-1)4

232/4 =n-1

58 =n-1

n=58+1

n=59

now S=n(a+l)/2

s=59(21+253)/2

s=8083