Math Logic

1. How can you make seven even?

2. What is the longest word in English?

3. Fill in the next three letters in the pattern O, T, T, F, F, S, S,.....

4. What weighs more : a pound of feathers or a pound of iron?

5. In a row of five persons, A is next to B. E is on right side of A who has D on his left side. C and D do not sit together. Who are sitting at the two ends of the row?

6. A shopkeeper has four weights (in kg) which enable him to weigh any commodity in whole number of kilograms up to 40 kg. He uses these weights on both pans of the balance, if necessary. Find the four weights he uses.

7. A person has nine coins, all looking alike but one of them slightly lighter than the others. Using a balance without weights, can he discover the lighter coin in just two weighings? If the number of coins is 12, how many minimum weighings will be required to find the lighter coin?

8. You have 10 stacks of coins with 10 coins in each stack. One stack of coins are all counterfeit and weigh one gram more than genuine ones. A genuine coin weighs 13 grams. Using a pointer scale (which shows the actual weight), what is the smallest number of weighings necessary to determine which stack is counterfeit?

9. A ship is at an anchor. Over its side hangs a rope ladder with rungs a foot apart. Eight feet of this ladder is above water when the tide begins to rise at the rate of 8 inches per hour. How much of the rope ladder will remain above water at the end of six hours?

10. Three boxes are labeled 'Apples', 'Oranges' and 'Apples and Oranges'. Each label is incorrect. You may select only one fruit from one box. (No feeling around or peeking permitted). How can you label each box correctly?

11. A peasant has to cross a river with his goat, dog and a bundle of grass. The boat can carry the peasant with only one more item in a trip. The goat if left with the grass will eat it. If the dog and the goat are left behind, the dog will bite the goat. What is the minimum number of crossings required to transfer all four to the other side?

12. A three centimeter cube has been painted red on all its sides. It is cut into one centimeter cubes. How many small cubes will be there in all? How many of these will be there with only
      -one side painted red
      -two sides painted red
      -three sides painted red
      -no side painted red?

13. Without lifting your pencil and without retracing your path, draw four straight lines that pass through all the given points.

14. Place five '*' in the grid so that there is no more than one '*' in each row, column or diagonal. Can you do it more than one way?