Saturday, 25 February 2017

Quibans 56: All you can eat

Thanks to Jamie for pointing me to this article, from the Daily Mail online:

How to BEAT the all-you-can-eat buffet: The expensive foods you should fill up on (and the cheap ones to avoid to get your money’s worth) 
The hacks were revealed on Channel 4's new documentary The 2,000,000 Calorie Buffet.The show, which airs on Monday, reveals that Brits spend around £4,000 on dining out a year.One of the most popular options for eating out is the all-you-can-eat buffet as you pay one low price - usually between £12 and £15 - and can eat as much as you like.But there's money to be made in this business - on a typical night, one of these restaurants can make £12,000. The show looks at the best ways to beat the buffet, as well as the tactics the restaurants employ to earn as much profit as they can.

1) Is it reasonable that “Brits spend around £4,000 on dining out a year”?
2) How much do we spend on food in a year?
3) Where does “2,000,000 Calories” come from?

1) This seems massively high.  It is about £10 per day (exactly £10 per day would be £3650 per year, which could sensibly have been rounded.  Taking the £12 cost of a buffet meal, that makes £4380, which also rounds to £4000, so you could have a buffet meal every day of the year.  Alternatively it is about £80 per week, which seems like an expensive meal to me. 

2) This is a nice opportunity to think about supermarket shopping (take the family bill for the week, subtract non-food items and then divide by the number of members of the family, add on other purchases (coffee, soft drinks, snacks, etc).

3) If a restaurant makes £12,000 per night and it costs about £12 then that requires 1000 customers.  If the average calorie intake per day is 2000 then multiplying the two gives 2 million calories.  (I have no idea whether that is where this comes from, but it seems plausible!)

Monday, 6 February 2017

Quibans 55: Super Bowl in Space

From the BBC website:

Super Bowl: Astronaut throws football '564,644 yards'
Nasa has released a video of the International Space Station crew preparing to watch the Super Bowl from 250 miles above Earth.

Show the first 3 seconds (and then stop it!) of the video.  The BBC article is here:
The video is also available on YouTube:

So: how fast is the International Space Station moving?
Given that the circumference of the earth is about 25,000 miles, how long does it take the space station to orbit the earth?

It travels 564,644 yards in about 64 seconds.  (Use the fact that the ball is released about 5 seconds into the video and the video says it lasts 1 minute 9 seconds.
Divide the number of yards by 64 to get 8822.563 yards per sec
There are 1760 yards in a mile.  So this is 5.01282 miles per sec
Multiply by 3600 to get 18046.15 mph
Given the estimates involved, round this off to 18,000mph.

The circumference of the earth is 25,000 miles, which gives a radius of 25,000 / (2*pi) = 3979
Add 250 (height of orbit of ISS) and then multiply by 2*pi() to get the circumference of the orbit = 26600.  Divide this by the speed to get 1.5 hours for one orbit.

(According to Wikipedia, one orbit lasts 92 minutes.)

Quibans 85: Crime and Police figures

From the Cambridge News: Violent crime in Cambridge has nearly doubled in a decade as police numbers drop 9 APR 2018 Bottom of For...