An enterprising businessman earns an income of Re 5 on the first day of his business. On every subsequent day, he earns an income which is just thrice of that made on the previous day. On the 10th day of business, he earns an income of:
Options:
(A) 21
(B) 22
(C) 20
(D) 45
(E) 30 Stream of consciousness:
2nd day he earns = 3(2 5)
3rd day he earns = 3(3 5)
On 20th day he earns 3(20 -5) = 45 rupees
Thus, the answer is (D).