If the annual rate of simple interest increases from 10% to 12 1/2 %, a man's yearly income increases by Rs. 1250. His principal in Rs. is?  Choose the correct choice from the following answers:	A) 34377	B) 50000	C) 777768	D) 2777	E) 27811
Let the sum be Rs. x. Then,   (x * 25/2 * 1/100) - (x * 10 * 1)/100 = 1250   25x - 20x = 250000   x = 50000   Answer: 50000
<result>B</result>
If the annual rate of simple interest increases from 10% to 12 1/2 %, a man's yearly income increases by Rs. 1250. His principal in Rs. is?