Subject :NCO Class : Class 10
Ans 3:
Class : Class 10
Sum of n terms  First Term = 99 
0.5 * n * [2a + (n1)d]  a = 99 
0.5 * 10 * [2a + 9d]  a = 99 
10a + 45d  a = 99 
9a + 45d = 99 
a + 5d = 11 > Eq 1

First Term + Fifth Term = 10 
a + a + 4d = 10 
2a + 4d = 10 
a + 2d = 5 
a = 5  2d > Eq 2

On Substituting Eq 2 in Eq 1 
5  2d + 5d = 11 
5 + 3d = 11 
3d = 6 
d = 2 

On Substituting d = 2 in Eq 2 
a = 5  4 
a = 1 

Third term =
a + 2d =
1 + 4 =
5