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 one
A) 10000 B) 30000 C) 50000 D) 60000 E) 20000
Let the sum be Rs. x. Then,   (x * 25/2 * 1/100) - (x * 10 * 1)/100 = 1250   25x - 20x = 250000   x = 50000   Option 50000
<result>C</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?