Respuesta :
Answer:8083
Step-by-step 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
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.
