daily express mensa teaser 17/05/12

[alison6399]

Hi

Please could someone shed some light on today's puzzle. The clue is as follows:

In a 'strongest man' competition, 2 men are pulling heavy vehicles over a 70-metre course. They both set off at the same point at the same time. If the 1st one completes the course at a speed of 55 metres per hour & the 2nd 1 does it at a speed of 45 metres per hour, how many minutes difference will there be in their finishing. Is the answer 10 minutes

Thanks

[Dave1970]

No not at all, if you think about where they are in an hour's time - one is at +55metres, but the other is at 45metres.

the first one completes the 70metres at 55metres/hour, so takes 70/55*60 minutes to complete. The second person does the 70m in 45mins, so takes 70/45*60 to complete it. About 19minutes I think

[Flyhalf]

In full minutes, yes (approx 43 and 53 mins).

[jomifl]

why? I make it 17 minutes

[Dave1970]

I should've said 45metres/hour, not 45mins*

[Dave1970]

And yes it's closer to 17 isn't it, my mental maths's iffy

[jomifl]

I used the same reasoning as Dave

[Flyhalf]

Scrub that, need to use different calculator!

[HowardKennitby]

I get 17 minutes

[grasscarp]

I made the difference 17 mins but could be wrong as calculator dying and almost too feint to read.

[bibblebub]

16.97979797..

[grasscarp]

I had to try and get it as I used to be a member of Mensa. When they started charging members to belong I got out!

[Flyhalf]

Used non-electronic calculator (myself), and concur with Dave1970.
Approx 76 and 93 mins.

[bigbadmarty]

just tried this - agree with jom 17mins

[Baldric]

16.97mins, call it 17

[Prudie]

Using time=distance/speed the difference is approx 17 minutes.

[jomifl]

so we are all agreed?