Question

find sum of 34+32+30+.....+10​

Answer 1

Step-by-step explanation:

34+32+30+28+26+24+22+20+18+16+14+12+10

Answer 2

Answer:

AP = 34 , 32 ,30 ......,10

So, a= 34 , d= 32 - 34 = -2 , an= 10

an = a+(n-1) (d)

10=34+(n-1) (-2)

10 = 34 -2n+2

10 -34=-2n+2

-24 = -2n +2

-24-2 = -2n

-26 = -2n

-26/-2 =n

n= 13

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

Sn = 13/2 + (2x34 + (13 -1 ) (-2)

Sn = 13/2 + ( 68 + (12)(-2) )

Sn = 13/2+(68-24)

Sn = 13/2+ 44

Sn = 286