Please do NOT post your answer, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.

I saw a friend of mine the other day. When I asked him how old he was, he said, “In two years I will be twice as old as I was five years ago.” How old is he?

Oh, and just a quick reminder that I am at the Edinburgh Fringe Festival on Sunday. Details

here (use the code PSYCHOB001 to get a 20% discount).

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called

**PUZZLED** and is available for the

**Kindle **(UK

here and USA

here) and on the

**iBookstore** (UK

here in the USA

here). You can try 101 of the puzzles for free

here.

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Took me about 12 minutes

finally i got one, friday puzzles had me stumped for a long time

Me too

Waiting for the puzzle…

Too easy.. Less than a minute.

Had an inkling, verified with simple algebra. Nice and simple in a couple of minutest.

Done-diddly-un

Hey “Captain” – love your screen name, it made me look back and double-check and of course, I misread the typo at first!

Only took me about 30 seconds. Thanks though

I got 27 answers. I believe all of them are right.

Do they include complex numbers?

Really?!?

I’m asking you!

One minute to find a pen and paper. Thereafter 10 seconds!

Got it. This time it took <1 Minute.

Under a minute.

A non-puzzle.

For the first time, I can honestly say that this took me less than a minute. Pen, paper, algebra. Tidy, as we say around these parts.

About a minute after I remembered my algebra.

Solved. Less than one minute.

Adrian Martienssen – Sent from Samsung Mobile 0…773

Richard Wiseman wrote:

Someone is sneakily answering it here.

That’s a pretty young friend you have Richard.

Simple equation! That’s it! took me less than a minute 🙂

Simple Equation… That is it.. took me less than a minute

less than two minutes

Less than 30 seconds using only trial & error

less than a minute

Pretty tricky actually. My first answer seemed a bit iffy so I tweaked the equation a bit. Let’s see what happens on monday..

I’m saying nothing.

Perhaps ‘cousin’ or ‘nephew’ might have been more appropriate than ‘friend’!

Wrote the equation as I read the question, solved within a few seconds.

well using algebra – the solution is trivial, but after doing that and rereading the puzzle, it came to me that carefully reading the puzzle, you can solve it rather simply in your head (i know you are still using algebra, but you can take a couple of shirtcuts, that makes it easy to solve in your head)

I tried that but it worked out too expensive to replace the cut shirts.

yes, but by the time I’d worked out that I could have done it in my head, I’d done it on paper (and then run it past the question again to ensure I hadn’t missed anything). The number of times I’ve thought “I should be able to do this in my head” and spent ages getting my brain in a knot (or making educated guesses that are anything like) – or missing the question – I tend to go for paper at the first resort

^ exactly what Søren said.

Ah Jaysus, if you needed pen and paper to solve that you probably had to ask your mammy for the pen

In other words you still haven’t solved it, right?

I solved it. It took me only less than 2 mins. I guess to solve it. Simple Algebra 🙂

Too easy. Need more of a challenge please.

I used excel

One minute using schoolchild algebra. Too easy.

Had an answer by the time I finished reading the question. then 5 seconds later realised that this was how old they’d be in two years time.

So essentially, we’re looking at (x+2) = 2(x-5)

That wasn’t too hard to solve 🙂

Dear mittfh.

Not a big reader, are you, cheese?

SN

Hey mittfy. What part of “Please do NOT post your answer” don’t you understand ?

mittfh did not post an answer.

Steve,

My thoughts exactly.

We could practically be identical twins.

Hey John. I take you point. While an equation is strictly not an answer it near-as-dammit is. Just a trivial solving for x gives the answer. An answer is important, especially the correct one but the working is also important and that is what mittfh essentially gave out. The answer easily follows from that.

Simple algebra. Less than a minute. I think even my 12 year-old brother could find out the solution to this one!

Took me less than a minute. Easy algebra is easy.

Are you ever in Chicago for a show?

Thank you,

Stephen Fossler

Date: Fri, 2 Aug 2013 07:30:33 +0000 To: stephenfossler@hotmail.com

Finally one I could solve!

But then in seconds, not minutes.

Is it really that easy, or have I missed something?

i have two solns to quadratic eq. took just a few mins.

This is not a puzzle but a (math) problem. 20 seconds.

Hi Deepfield (strangely where I live is called Deepfield), I think we had this ‘debate’ before whether a math’s problem is a puzzle or not. http://www.dictionary.com defines a puzzle as: “toy, problem, or other contrivance designed to amuse by presenting difficulties to be solved by ingenuity or patient effort.”. So a problem, maths or otherwise can be a puzzle.

A very simple simultaneous equation. Even after 4 glasses of wine, it only took 4 seconds though I am prone to exaggerate by a factor of 4 when I have had 4 glasses of wine

You’re probably wondering. I’ve now had 5 glasses of wine. By how much am I exaggerating? This is better than richard’s puzzle

Hey Phil. “simultaneous equations” ? It’s not two equations in two unknowns but one equation in one unknown i.e. it’s not a simultaneous equation. Maybe the wine was making you see double ? Maybe you only drank 2 glasses of wine ?

steve – as i ans’ed above, is two answers so must be simultaneous eqn. see previous above for more.

Hi Dharmaruci. Mittfh gave one equation in one unknown above, which is what I had. I’d like to see your simultaneous equations for two solutions. Can you send to me via email ?

Maybe Dharmaruci’s friend is imaginary – but I think not

It took me a day the answer is ***** can’t wait to see the answer 😥

Please reply

Less than a minute. It’s a good thing you didn’t say, “I saw an old friend…”

Too easy.

Easy for you and hard for others perhaps. We don’t all have the same ability. Perhaps a different site if this one’s not chanllenging enough. This one http://uktv.co.uk/dave/homepage/sid/9132 is good. TV series was good too.

Nice one! Took about a minute to freshen the gray matter.

\

I love algebra. Simple, but not immediate. I had to get a pencil and paper, and then it only took half a minute.