17-Jan
Question
You have 50 bags, each holding about 100 balls. You have a digital weighing machine with 3 places of decimals on the display, calibrated in grams. All of the balls in all bags weigh 1 gram, except in one bag all of the balls weigh 1.001 grams. How do you find this bag? All bags look and feel the same and you can only use the weighing machine once before it self destructs.
Answer
Take one ball from the first bag, two from the second, three from the third and so on. Thus, the total weight of all the balls would be 1275 ( 50 * 51 / 2 ) gms., if all the balls were exactly 1.000 gms. But since some balls were heavier, the balance would show a little more than this. Thus, whichever bag had the heavier balls, the excess amount will be a multiple of 1, 2, 3, ... This number will tell you which bag has the heavier balls. Thus if the excess is 0.037, it means the 37th bag has the heavier balls.
24-Jan
Question
200% of 50% equals?
Answer
100
31-Jan
Question
3 people go to a hotel. They pay $30 and go to their room. The manager realises the room rate is $25 so gives $5 to the bellboy to return. On his way the bellboy reasons that $5 would be difficult to share among 3 people so he pockets $2 and gives $1 to each person. Now each person paid $10 and got back $1. So they paid $9 each, totalling $27. The bellboy has $2, totalling $29. Where's the other $1?
Answer
The bellboy's $2 should be added to the manager's $25 or subtracted from the tenants' $27, not added to the tenants' $27.
07-Feb
Question
5 athletes ran a 10,000m race. Athlete C placed 3rd & athlete E placed 2nd. From the following information, can you tell how athletes A, B & D were placed in the race? Athlete A was not last. Athlete A came in after E. Athlete D was not 1st.
Answer
The athletes finished in the following order; B,E,C,A,D
14-Feb
Question
A bakery lowered its price for biscuits from 25c to 20c each. For $4, how many more biscuits could you buy now than before?
Answer
4
21-Feb
Question
A boy was asked to multiply 5 numbers together. He was shown each number in turn, but before even seeing the last 2 numbers, he gave the correct answer. How did he do it?
Answer
The third number was zero. Therefore the total became zero and would stay the same whatever the final 2 numbers were.
28-Feb
Question
A farmer needs to cross a river in a boat with her wolf, pig & some cabbages. There are no bridges & the boat is only big enough for the farmer and 1 item. If she leaves the pig alone with the cabbages the pig will eat them. If she leaves the wolf alone with the pig the wolf will eat the pig. How can the farmer safely cross the river with all 3 items?
Answer
First the farmer takes the pig across the river. He goes back to pick up the wolf. When he is across he leaves the wolf and takes the pig. Back on the other side he leaves the pig and takes the cabbages with him. Then he picks up the pig and all three items are on the other side of the river.
07-Mar
Question
A father is four times as old as his son. In 20 years he will be twice as old as his son. How old are father and son now?
Answer
The father is 40 and the son is 10.
14-Mar
Question
What belongs to you but gets used by everyone else more than you?
Answer
Your name
21-Mar
Question
A number is halved and the result is squared. This gives an answer that is twice the size of the original number. What was the original number?
Answer
8
28-Mar
Question
A square lawn has a path 1 metre wide around the outside of all the 4 edges. The area of the path is 40 square metres. What is the area of the lawn?
Answer
81 square metres
04-Apr
Question
A woman tied a rope around the earth. She used 40,000km of rope to do it. Her sister did the same thing only she had the rope on sticks 1m above the ground. How much rope did she use?
Answer
2pi, approximately 6 meters