In an AP:
(i) given a = 5,d=3, `a_n`
= 50, find n and `S_n`
.
(ii) given a = 7, `a_(13)`
= 35, find d and `S_(13)`
.
(iii) given `a_(12)`
= 37, d= 3, find a and `S_(12)`
.
(iv) given `a_3`
= 15, `S_(10)`
= 125, find d and `a_(10)`
.
(v) given d = 5, `S_

A. 5

B. 6

C. 7

D. 8