Question

1+3+5+7+9+11+13+15 . Find it without calculation

Answer 1

Hey

1+3+5+7+9+11+13+15

a=1, d=3-1=2, n=8
sn = n/2[2a+(n-1)d)]
s8= 8/2[2(1)+(8-1)(2)]
s8 = 4[2+7(2)]
s8=4(2+14)
s8=4(16)
s8= 64 ANSWER..

HOPE IT HELPS:-))

Answer 2

this is right process to solve this sums


if it helps mark as brailleast