Question

Find the sum :

(i) 6 + 13 + 20 + ....to 19 terms.​

Answer 1

Answer:

(6+13+20+27+34+41+48+55+62+69+76+83+90+97+104+111+118+125+132 = 9429

Step-by-step explanation:

in question nimbers are on gapes of 7 that why answer is 9429

Answer 2

Answer:

56

Step-by-step explanation:

a=6, d=7 .

Sn = n/2 × t1 + tn

19/2× 6+132

= 19/2×138

= 19×69

=1311.