Malcolm is the number of weeks of his father’s age treated as days and his grandfather’s age in months. All three of their ages add up to 120 years. How old is Malcolm, his father and his grandfather?
Supposedly this is given as a test in Japan. I have no idea if that’s accurate.
There are 8 people who have to cross the river on a raft.
1. Policeman
2. Thief
3. Father
4. Boy 1
5. Boy 2
6. Mother
7. Girl 1
8. Girl 2
The rules are:
Only two people can cross at a time.
Only the adults can operate the raft.
The father can’t be with the girls unless the mother is there.
The mother can’t be with the boys unless the father is there.
The thief can’t remain with anyone unless the policeman is present.
How do you get them all across?
Instead of working it out by hand, here’s a flash version.
Click on the circle to start. Click on a person to put them on the raft and click on the lever to make the raft cross.
Four different-colored balls are being used in a gym class activity – blue, red, yellow and orange. Each student must hold two different-colored balls, but no two students can have the same two colors (for example, only one student can hold the blue and red ball).
On Arbor Day the fourth grade class began planting trees. They finished planting five trees before the fifth grade class arrived. But they accidentally planted them on the fifth grade side of the street.
The fourth-graders crossed the street to start over, and the fifth-graders planted the remaining trees. They finished first and felt bad for the fourth-graders, so they crossed the street and planted five trees. They planted another five trees at which point all of the trees had been planted.
By how many trees were the fifth-graders ahead of the fourth-graders?
Four. If the apples are A, B, and C, it’s possible that you could take out one A, one B and one C with three apples, but the fourth apple must be one of the three kinds.
Three philosophers are taking a nap under a tree. While they’re asleep, a small boy smears their noses with red berries. When they awake, they each begin to laugh, thinking the other two are laughing at each other.
But then one philosopher stops laughing, realizing his nose is red too. How did he come to this conclusion?
Let’s call the philosopher’s A, B and C. A reasoned that B was confident his nose wasn’t red. If B saw A’s nose wasn’t red, he would be surprised that C was laughing, because C would have nothing to laugh at. But B wasn’t surprised, therefore, A correctly reasoned his nose was smeared.
A delivery truck from the post office is sent to the airport to meet a cargo plane at its planned arrival time. The plane lands ahead of schedule and its contents are brought toward the post office by bicycle. After a half hour, the bicycle meets the truck and the mail is transferred.
The truck returns from the post office 20 minutes early. How early did the plane arrive? (Assume all transactions are instantaneous)
The delivery truck arrived back 20 minutes early, so it would have taken 20 minutes to go from where it met the bicycle to get to the airport and back. Therefore, the bicycle and truck met when the truck was 10 minutes from the airport. Adding those 10 minutes to the 30 minutes the truck had already driven to meet the bicycle means the plane arrived 40 minutes ahead of schedule.