Solution:

20 paisa coins : 200
25 paisa coins : 124

Explanation:
Say he collect 20-paisa coins be A
Say he collect 25-paisa coins be B
=>number of 25-paisa coins = (324 - A).

Therefore,
0.20 X A + 0.25 (324 - A) = 71
=>20A + 25 (324 - A) = 7100
=>5A = 1000
=>A = 200.

Hence, number of 25-paisa coins = (324 - A) - 124.

Solution:

Treasure Map Is Hidden Inside The Hanging Room Floor.

Explanation.
Just reverse the text "roolF mooR gnignaH ehT edisnI neddiH sI paM erusaerT".

Solution:

99 matches.

The number of matches will always sum up to one less than the number of players in a knock out tournament. You may calculate it in any manner. Thus 99 matches were played.

Solution:

16-days

In 15-days, he will climb 15-inch and when he climbs 5 inch more, he will be out of the well :-)

Solution:

Colors:
Y B R G
G R B Y
B Y G R
R G Y B


Signs:
x + - /
- / x +
/ - + x
+ x / -

Solution:

A cigar stuck in the wall

Solution:

Can be found on the pic below.

Solution:

3 1 2 2 1 1
1 3 1 1 2 2 2 1

Read Line as one 1 => 1
Read Line 2 as two one => 2 1
Read Line 3 as one two and one one => 1 2 1 1
and so on.

Solution:

They used the planks in the manner that is shown in the figure.

Solution:

3/7

Explanation:
If a 31day month starts on a Friday, Saturday or Sunday it will have five Sunday, if not it will have 4 Sunday.

Solution:

Bond was suspicious of the women as one never knocks its own door at the hotel.