An enterprising businessman earns an income of Re. 1 on the first day of his business. On every subsequent day, he earns an income which is just double of that made on the previous day. One the 10th day of business, his income is

Question: An enterprising businessman earns an income of Re. 1 on the first day of his business. On every subsequent day, he earns an income which is just double of that made on the previous day. One the 10th day of business, his income is
[A].

Rs. 29

[B].

Rs. 210

[C].

Rs. 10

[D].

Rs. 102

Answer: Option A

Explanation:

Income on the first day = Re. 1.

Income on the 2nd day = Rs. (1×2) = Rs. 21.

Income on the 3rd day = Rs. (21 x 2) = Rs. 22 and so on. Thus, Income on the rath day = Rs. 2n-1.

Therefore Income on the 10th day = Rs. 29.

A farmer built a fence around his square plot. He used 27 fence poles on each side of the square. How many poles did he need altogether ?

Question: A farmer built a fence around his square plot. He used 27 fence poles on each side of the square. How many poles did he need altogether ?
[A].

100

[B].

104

[C].

108

[D].

None of these

Answer: Option B

Explanation:

Since each pole at the corner of the plot is common to its two sides, so we have :

Total number of poles needed = 27 x 4 – 4 = 108 – 4 = 104.