Power Outage Riddle
Julie is going on an extended trip for three weeks. She lives in a remote area where there are frequent electrical power outages which can last up to three or four days. Julie has quite a bit of food in her freezer which would go bad if it thawed and then re-froze. She does have digital clock and a VCR which would flash 12:00 if the power went out. Unfortunately the clock and VCR flash even if the power only goes out for a few seconds. What can Julie do so that when she returns home she will be able to determine whether the power was out long enough to thaw her food? Asking a neighbor whether the power was out, isn't a reliable option because the nearest house is half a mile away, and one house may have power, while another house may have no power. She won't be able to have a neighbor check on her house every day, and has no one to house sit.
Hint:
One thing Julie could do is freeze a tray of ice-cubes, and turn the tray of ice upside down in her freezer. When she comes home, she should check the tray. If the ice cubes are still in the tray, the food is safe to eat. If the trays are empty, it's time to clean out the freezer. She will have to make a judgment call if the ice-cubes are only slightly thawed. Did you answer this riddle correctly?
YES NO
YES NO
Losing The Bet Riddle
John bets Tom $100 that he can predict the score of the football game before it starts. Tom agrees, but loses the bet.
Why did Tom lose the bet?
Why did Tom lose the bet?
Hint:
John said the score would be 0-0 and he was right. "Before" any football game starts, the score is always 0-0. Did you answer this riddle correctly?
YES NO
YES NO
Lemons Cross The Road Riddle
Hint:
Joe's 10 Coins Riddle
Joe has ten coins totaling $1.19. From these coins, he cannot make exact change for a dollar, half-dollar, quarter, dime, or nickel.
What are the coins?
What are the coins?
Hint:
Don't Be Tardy Riddle
My dewy voice and sappy smile
Will lure you to my tower,
But do not tardy, for you can't be late,
And the walk is half an hour.
Who am I?
Will lure you to my tower,
But do not tardy, for you can't be late,
And the walk is half an hour.
Who am I?
Hint:
Which Did They See Riddle
There were 2 children, the son and the daughter. The daughter was born on January 20th and the son was born on March 12th. Both of them were born in the morning. Which one did their parents see first?
Hint:
Spin Me Like A Top
I am a toy that Jewish children play with. You spin me like a top. I have Hebrew letters on each side. What am I?
Hint:
Given Each Night Riddle
Hint:
Drowning Fish Riddle
Hint:
Rope Burn Riddle
You have two ropes. Each rope takes one hour to burn. These ropes are not identical, nor are they uniform; i.e. it does not necessarily take half an hour for half the rope to burn (if you have trouble visualizing this, imagine a rope of varying thickness across its length). With only these two ropes and a way to light them, how do you measure out 45 minutes?
Hint: You can light multiple ends and/or multiple ropes at the exact same time.
Light both ends of one rope, and only one end of the other rope. This will cause the first rope to burn out in 30 minutes. When the first rope burns out, there will be 30 minutes left on the second rope. So then, light the other end of the second rope, and the rest of it will burn out in 15 minutes. 30 + 15 = 45 minutes. Did you answer this riddle correctly?
YES NO
YES NO
Prince Age Riddle
A princess is as old as the prince will be when the princess is twice the age that the prince was when the princess's age was half the sum of their present ages.
What are their ages?
What are their ages?
Hint:
Current Future Past
Princess x 2z (x+y)/2
Prince y x z
I then created three equations, since the difference in their age will always be the same.
d = the difference in ages
x y = d
2z x = d
x/2 + y/2 z = d
I then created a matrix and solved it using row reduction.
x y z
1 -1 0 d
-1 0 2 d
.5 .5 -1 d
It reduced to:
x y z
1 0 0 4d
0 1 0 3d
0 0 1 5d/2
This means that you can pick any difference you want (an even one presumably because you want integer ages).
Princess age: 4d
Prince age: 3d
Ages that work
Princess:
4
8
16
24
32
40
48
56
64
72
80
Prince:
3
6
12
18
24
30
36
42
48
54
60 Did you answer this riddle correctly?
YES NO
Princess x 2z (x+y)/2
Prince y x z
I then created three equations, since the difference in their age will always be the same.
d = the difference in ages
x y = d
2z x = d
x/2 + y/2 z = d
I then created a matrix and solved it using row reduction.
x y z
1 -1 0 d
-1 0 2 d
.5 .5 -1 d
It reduced to:
x y z
1 0 0 4d
0 1 0 3d
0 0 1 5d/2
This means that you can pick any difference you want (an even one presumably because you want integer ages).
Princess age: 4d
Prince age: 3d
Ages that work
Princess:
4
8
16
24
32
40
48
56
64
72
80
Prince:
3
6
12
18
24
30
36
42
48
54
60 Did you answer this riddle correctly?
YES NO
10 Cookies Riddle
A babysitter came over one day to babysit 10 children. She decided to give them a snack. In a jar there were 10 cookies. She wants to give each one a cookie, but still keep one in the jar. How will she do it?
Hint:
She hands the 10th child the jar with one cookie left in it. Did you answer this riddle correctly?
YES NO
YES NO
Strawberry Resemblance
Hint:
Chances Of A 2nd Girl Riddle
Tipli and Pikli are a married couple (dont ask me who he is and who she is)
They have two children, one of the child is a boy. Assume safely that the probability of each gender is 1/2.
What is the probability that the other child is also a boy?
They have two children, one of the child is a boy. Assume safely that the probability of each gender is 1/2.
What is the probability that the other child is also a boy?
Hint: It is not 1/2 as you would first think.
1/3
This is a famous question in understanding conditional probability, which simply means that given some information you might be able to get a better estimate.
The following are possible combinations of two children that form a sample space in any earthly family:
Boy - Girl
Girl - Boy
Boy - Boy
Girl - Girl
Since we know one of the children is a boy, we will drop the girl-girl possibility from the sample space.
This leaves only three possibilities, one of which is two boys. Hence the probability is 1/3 Did you answer this riddle correctly?
YES NO
This is a famous question in understanding conditional probability, which simply means that given some information you might be able to get a better estimate.
The following are possible combinations of two children that form a sample space in any earthly family:
Boy - Girl
Girl - Boy
Boy - Boy
Girl - Girl
Since we know one of the children is a boy, we will drop the girl-girl possibility from the sample space.
This leaves only three possibilities, one of which is two boys. Hence the probability is 1/3 Did you answer this riddle correctly?
YES NO
The Gardners Riddle
Gretchen and Henry were discussing their new neighbors, the Gardners. Gretchen mentioned that she met two of the daughters, and they each had blond hair.
"I have met all of the sisters," replied Henry, "and the probability that both of the girls you met would have had blond hair, assuming you were equally likely to meet any of the sisters, is exactly 50%. Do you know how many children there are?"
After thinking for a minute, Gretchen asks if the family is abnormally large. When Henry replies that it is not, Gretchen tells him how many girls are in the family. What number did she say?
"I have met all of the sisters," replied Henry, "and the probability that both of the girls you met would have had blond hair, assuming you were equally likely to meet any of the sisters, is exactly 50%. Do you know how many children there are?"
After thinking for a minute, Gretchen asks if the family is abnormally large. When Henry replies that it is not, Gretchen tells him how many girls are in the family. What number did she say?
Hint:
Gretchen said that there were 4 girls in the family, three of whom were blond.
This would make the probability that she saw two blonds (3/4) * (2/3), which equals 1/2.
Other numbers would work, but the next pair would lead to a rather large family. Did you answer this riddle correctly?
YES NO
This would make the probability that she saw two blonds (3/4) * (2/3), which equals 1/2.
Other numbers would work, but the next pair would lead to a rather large family. Did you answer this riddle correctly?
YES NO
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