Puzzle time: The last puzzle given by my brother in law – I am still trying to decipher the answer from three of my friends – one of whom is the brainy-types and has changed his mind thrice….

But today is Thursday and I should be flying home…. so here is one that is easier …

How do you get 100 using one “1” and four “7”s. You can use plus, minus, multiple, divide symbols and parentheses.

e.g. 177-77

Now give me another answer…

If you have cracked it, send me PM. I will recognize you publicly…

New puzzle!! Like every other responsible brother-in-law, I called up my BIL this morning to check on him and his family. As is his wont, he immediately rewarded me with a puzzle which has stumped me ever since. (I think he is trying to give me a hint 🙂 ). Anyways, I got to the answer intuitively (and I am assuming it is the correct answer since he confirmed it) but for the life of me, I cannot come up with a proof for the answer.
So, here it is: Think of a circle. Now think of all the n-sided regular polygons that can fit in it (all the vertices of the regular polygon will touch the circumference of the circle). Which figure (i.e. for what value of “n” – triangle, square, pentagon, hexagon, heptagon, octagon etc etc ) will have the maximum value for the sum of squares of the sides.
As always, if you know or crack it, send a PM. I will acknowledge in the common forum.

Finally found a great and logical answer to the question – Why do those clocks snooze for 9 minutes? (instead of a more logical 10 minutes or 15 minutes ….). You may have already known it but I did not. Before I tell you what I read, let me ask you – why do you think it is that way?

I got this puzzle from my brother-in-law today (all your jokes about troubles created by inlaws to be inserted here 🙂 ). I believe I have arrived at the right answer but since he does not know the answer himself, would like to see if others can prove or disprove me.
A car’s wear and tear pattern is such that any new tire put in the front can last 40,000 miles and the ones in the rear can last 60,000 miles. You are given four new tires to begin with and you can interchange the tires between front and rear as many times as you want. What is the maximum distance you can drive?

Strictly speaking, it is not puzzle time since I am flying out of Atlanta not to Atlanta. But what the hell, it is holiday season… so, here goes..
I was addressing a large audience this morning and asked those who have two kids to raise their hands. Then I asked – of all the people who have their hands raised – to keep their hands raised if one of their child is a son born on a Sunday. They rest can put their hands down. Now I picked any one from the ones left with their hands raised. What is the probability that their other child is a son?
(assume equal probability for having a son or a daughter or which day of the week a child is born).

It has been a tough time travel wise. Always weird when you fly back to home town for a few hours and not see your family. Anyways, on to more important things.. puzzle time…

Imagine a vertical tree 80 ft tall and a crow sitting right on the top of it. Now imagine a vertical tree 60 ft tall about 100 ft away from the first tree. The crow wants to fly to the top of the second tree BUT has to hit the ground once first enroute (essentially flying in two straight lines). What is the point on the ground it should hit so that it has to fly the least distance in all? 

Don’t worry about the dimensions. Think about the intuitive answers…

It is Thursday evening and I did not travel this week. But I had a long long day. So, it counts as travel. And thereforre, here goes the next puzzle (variation of the standard tiger, goat, pile of grass and a man crossing the river):
3 missionaries and 3 cannibals are trying to cross a river filled with piranhas. The boat can take max 2 of them at a time. But if the cannibals outnumber the missionaries at any point of time, they will eat them up. How can they cross safely?

So here is a puzzle that occurred to me while running yesterday (I know, I know, I need to get a life 🙂 ) Two runners start from point A and run at uniform (but different from each other) speeds to a point B exactly a mile apart and run back and keep doing this till they meet at either end (A or B). If their speeds are “m” mins/mile and “n” mins/mile (m not equal to n, and m and n are whole integers), how would you find out after how many minutes will they meet (they stop if they meet at A or B)?

Usually, I fly home on Thursdays. This time I am flying out on Thursday. Nonetheless, puzzle time. Fill in the dashes with the digits 1, 2, 3, 4, 5 and 6 so that the equality stands. (the evaluation is done strictly from left to right – so 6 – 2 x 3 = 12 and not 0).

_ + _ – _ x _ / _ x _ = 50

Puzzle for this week…
How can you cut a perfectly circular homogeneous cake into eight parts of same shape and size with three straight cuts? As always send me a message if you know or solved it…