Two employees X and Y are paid a total of Rs. 638 per week by their employer. If X is paid 120 percent of the sum paid to Y, how much is Y paid per week?  Pick:
A) s . 250
B) s . 280
C) s . 290
D) s . 299
E) s . 300

Rationale: "let the amount paid to x per week = x and the amount paid to y per week = y then x + y = 638 but x = 120 % of y = 120 y / 100 = 12 y / 10 ∴ 12 y / 10 + y = 638 ⇒ y [ 12 / 10 + 1 ] = 638 ⇒ 22 y / 10 = 638 ⇒ 22 y = 6380 ⇒ y = 6380 / 22 = 580 / 2 = rs . 290 c"
Answer: C