The first term of an A.P. is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.
a = 5, l = 45
Sn= 400
[5 + 45] = 400
[50] = 400
n = 16
16th term is 45
a16= 45
5 + 15d = 45
15d = 40
d = 
30
The first term of an A.P. is 5, the last term is 45 and the sum is 400. Find the number of terms and the common difference.
a = 5, l = 45
Sn= 400
[5 + 45] = 400
[50] = 400
n = 16
16th term is 45
a16= 45
5 + 15d = 45
15d = 40
d =