Answer: 14
Explanation:
Given the sequence : 55 176 539 1628
Each number after the first is derived by multiplying by x and then adding y;
If x and y are > 0 and they are integers.
Taking 55 and 176:
176 = 55*x + y
539 = 176*x + y
55x + y = 176 - - - (1)
176x + y = 539 - - (2)
From (1) y = 176 - 55x
Substitute y = 176 - 55x into (2)
176x + 176 - 55x = 539
121x = 539 - 176
121x = 363
x = 363 / 121
x = 3
Put x = 3 in y = 176 - 55x
y = 176 - 55(3)
y = 176 - 165
y = 11
x = 3, y = 11
x + y = 3 + 11 = 14