Biologists always knew how geckos do Spiderman tricks with ?lan. What baffled them was how the different shapes present on the limbs of these wall-climbers performed. Now, says Nature News, ?New equations enable them to compare different shapes. These equations could allow us to design artificial surfaces that stick to walls better than anything found in nature? Two years ago scientists proved that geckos use intermolecular attractions, known as van der Waals forces, to climb walls. The mathematical models available have assumed that all the contacts were spherical. The new model found that if you assume a completely even surface, flat contacts perform best because they maximise the amount of surface contact. Place your orders for a new set of Spiderman suits! Hurry, stocks limited!.

PUZZLE 1: Halloween was almost over, and Mr Green had less than 20 candies left. When the doorbell rang, he thought he would give all the candies away. When he opened the door, there were two trick-or-treaters. He wanted to give away the candies evenly, but he noticed that when he divided the candies in two, there was one left over. At that point, he saw another trick-or-treater behind the first two. He tried to divide the candies evenly among the three of them, but again one was left over. Finally, another trick-or -treater came to his door, making it four trick-or-treaters altogether. Mr Green still had one candy left over after dividing the left-over candies in fours. How many candies did Mr Green have left when the doorbell rang?

PUZZLE 2: Clark, Daw and Fuller make their living as carpenter, painter and plumber, though not necessarily respectively. The painter recently tried to get the carpenter to do some work for him, but was told that the carpenter was out doing some remodelling for the plumber. The plumber makes more money than the painter. Daw makes more money than Clark. Fuller has never heard of Daw. What is each man's occupation?

Solutions on December 6

CORRECT ENTRIES

November 8

Dibyen Das, Cal-19; Richa Mehta, Heritage Institute of Technology; Jnanendra Nath Ray, Cal-48; Shayak Bhattacharjee, Patha Bhavan; Vishal Lama, Siliguri; Debasis Ganguly, Alumnus Software; Vinode Verma, Cal-43; Shouvik Chattopadhyay, Sodepur; Abhinandan Khan, Dum Dum; Binay Kumar Choubey, Asansol; Sreechandra Banerjee, Cal-19; Shyamashree Shill and Kamala Mookherjee, Kharagpur

CORRECT ENTRIES

November 1

Sandeep Garg, Howrah; Debjani Ghosh, Rabindra Nagar, Behala; Bappaditya Banerjee; Teghoria; Radhamohan Kejriwal, Ranigunje; Debasis Hazari, Bilaspur; Chirantan Sarkar, Cal-28; S. Krishnaiyer; Cal-8

PUZZLE CRACKED

Solution 1: An orange costs 5 cents, a lollipop 4 cents and toffee sticks 3 cents.

Hints: Let us assume that the number of oranges bought by Margaret is ?m? and that by Mike is ??. The prices of the oranges, lollipops and the toffee sticks may be assumed as ??, ?L? and ?T? cents respectively. According to the puzzle, (i) mxO + 6xL = 43 and (ii) nxO + 7xT = 43. From this we can deduce (a) (m-)xO=7xT - 6xL (b) mxO = 43 - 6xL and (c) nxO = 43 - 7xT.

Solution 2: The ages are 28, 26 and 25

Let the total life span of the three liars, starting from the oldest be x, y, and z. Therefore, x/2 + 2y/3 + 2z/3 = 130. Again, 30>x/2>y/3>z/3. By trial and error, we arrive at a solution x = 56, y = 78, and z = 75. This means that their present ages are 28 years, 26 years and 25 years.

Solution 3: Jim had a better average.