Question

find the sum of 111terms of an Ap whose 56th term is 5÷37

Answer 1

T56=5/37 , and S111= ?

S111 = n/2[2a+(n-1)d]

= 111/2[2a+110d]

=111/2 *2[a+55d]

=111/2*2[5/37]

=3*5

=15