Gold is a very heavy metal, So if he will carry it by himself a single  parachute will not  hold him, and the gold. Also if nobody knows that he killed the passengers (even the pilot doesn’t know), than the government  might thing he will release while the plane is in the air and fly with the elsewhere

Answer: Certain
The average of umber of arms is less then two because of people born without arms  or with one arm or lost it by accident. So all the normal people who have 2 arms are above the average.

answer: 6 pm
24 hours a day. What interest us is how much hours at the last day after 23,999,997 hours. So 23,999,997 /24 = 999,999.875 days.  0.875 days * 24 hours =21 so 9pm + 21 hours = 6pm

7 members
The first couple are the Grandfather and the Grandmother. They have a son . the son is married. and they have 3 children: 1 son and two daughters.
So:
The grandfather is also father (of his son)  and his son is also a father >>> 2 fathers
The grandmother is also a mother (of her son), and the wife of the son is also a mother >>>> 2 mothers
The grandfather is for his son wife, a father-in-law and the grandmother is a mother-in-law to her>>> one father-in-law and one mother-in-law
The son  has 3 children so we have >>>  4 children
His 3 children are grandchildren to his parents. >>> 3 grandchildren
The son has 1 boy and 2 girls so the girls have >>one brother  and the boy has >> two sisters
The son’s wife is the daughter-in-law

Since the clock is symmetric than  we can calculate the time as if the distance should be the same from 12 o’clock.

The general approach to solving problems like this is to take into consideration the rate of change of the angle per minute.
The hour hand makes a complete rotation of 360 degrees in 12 hours. In other words, 360 degrees in 720 minutes,
which means 0.5 degrees per minute.
The minute hand rotates 360 degrees per hour, meaning 6 degrees per minute.

And so the angle formula for the hour hand will be:
0.5* the hour according to the hour hand * 60 (minutes in an hour) + 0.5* the number of minutes according to the minute hand.
The formula for the minute hand is: 6 * the number of minutes according to the minute hand.
So in our question if we mark the hour hand with H and the minutes hand with M we can write the question as:
0.5*H*60 + 0.5*M = 360 -6M >> 6.5M = 360 -30H

So the solutions are:
1) 1:50:46
2) 2:46:09
3) 3:41:32
4) 4:36:55
5) 5:32:18
6) 6:27:41
7) 7:23:04
8) 8:18:27
9) 9:13:50
10) 10:09:13
11) 11:04:36
12) 12:00:00  

72
Let the space be X and number of buses today Y. Before expanding X was enough for Y-12 buses. After expanding 40% it can contains Y+12 buses
so   1) X = y-12 >> y = x+12
2) 1.4x = y+12 >> 1.4x = x +12+12  >> 0.4x = 24 >> X=60  >> y =x+12 > 72

Sum of numbers 1-9 is 45 so it can’t be slitted into 2 equal groups. But given that  6 cannot be flipped over to make it 9 does not mean the opposite is also true, so if we flip the 9 to be 6 the sum is 42 which can be split to 21 for each group.
So the groups are 1+2+3+4+5+6=21 and 6+7+8=21

You don’t bury survivors. Only dead people

Playing Chess with D.

The question in not clear enough.  Because when sayin that: You can choose any bulb and change the neighbor’s state i.e. ON to OFF or OFF to ON, does it mean that I must change both neighbors or can I choose to change only one of them? Also it is not clear if when asking “What is the maximum number of bulbs we can turn on?” means also how many will stay turned on or only how many can be turned on?

Lets check all the cases:
If we must change the state of both the neighbors than we have 3 cases
1) the bulbs are next to each other like 001100 than we can light all the bulbs but only 2 will stay on
2) If there is a gap of one between the 2 bulbs like 010100 than we can light all the bulbs but only 4 will stay on
3) If the gap is greater than 2 all the bulbs can be light but only 6 will stay on
If we don’t have to change the state of all the neighbors than we can light all the bulbs  and all of them will stay on.