Consider the question. 4000 was divided into two parts such a way that when first part was invested at 3% and the second at 5%, the whole annual interest from both the investments is Rs.144, how much was put at 3%?
Options:
(A) 2800
(B) 2500
(C) 2700
(D) 3000
(E) 3500
If the answer is '(A)'; explain the reasoning:
(x*3*1)/100 + [(4000 - x)*5*1]/100 = 144
3x/100 + 200 5x/100 = 144
2x/100 = 56 e x = 2800