Question

Please solve the problem .....

Answer 1

(i) a= 1

an=50

Sn= n/2(a+an)

d=1

an= a+(n-1)d

➡️50= 1+(n-1)*1

➡️50=1+n-1

n=50

➡️Sn=50/2(1+50)

➡️Sn= 25*51

Sn=1275.

SIMILARLY,

(ii)a=31

an=50

d=1

an=31+(n-1)*1

➡️50=31+n-1

➡️50+30=n

n=80

➡️Sn=40*(31+50)

➡️Sn=40*81

Sn=3240.

Answer 2

hope it will help you