If the first four terms are
x – 3d, x – d, x + d, x + 3d
x – 3d + x – d + x + d + x + 3d = 100
4x = 100
x = 25
i. If d = 1
The arithmetic sequence is 22, 24, 26, 28
ii. If d = 2
The arithmetic sequence is 19, 23, 27, 31
iii. If d = 3
The arithmetic sequence is 16, 22, 28, 34
iv. If d = 4
The arithmetic sequence is 13, 21, 29, 37