In an AP :
given d = 3, a12 = 37 find a and s12
d is the common difference = 3
a is the first term
a12 = 37
a12 = a + (12-1)d
37 = a + (11)3
a = 4
The sum of the series is Sn = 
[2a + (n-1) d]
S12 = 
[2×4 + (12-1)×3]
= 6 [41]
= 246
3
In an AP :
given d = 3, a12 = 37 find a and s12
d is the common difference = 3
a is the first term
a12 = 37
a12 = a + (12-1)d
37 = a + (11)3
a = 4
The sum of the series is Sn = [2a + (n-1) d]
S12 = [2×4 + (12-1)×3]
= 6 [41]
= 246