TV1 and TV3 6PM News Ultimate Maths Fail

By Steve Biddle, in , posted: 9-Feb-2010 19:14

If you were (un)lucky enough to watch TV1 or TV3's 6PM news broadcasts tonight you were witness to a classic maths failure from both networks - the inability to correctly calculate a proposed 2.5% increase in GST.

Both networks showed a list of prices and calculated the new price with a 15% GST. Both failed miserably when it came to such a simple calculation and have no doubt confused an entire country.

When a product sells for $1500 the GST component of that price is $166.66 (rounded to 2 decimal places) and the GST excl price of the product is $1333.33 (rouded to 2 decimal places).

To deduct GST from a price divide it by 9 to establish the GST value or divide it by 1.125 to establish the GST exclusive amount,

Both networks simply added 2.5% onto the existing GST inclusive price which is wrong and does not give the correct amount. To calculate the new 15% GST inclusive price, the current 12.5% GST needs to be deducted from the current retail and the new 15% GST rate added to this GST excl price.

On TV3's example of a $1500 TV they show the new price of $1537.50, a $37.50 increase. 15% GST on the GST excl price of $1333.33 is $200.00, giving a new retail of $1533.33, a $33.33 increase.

On TV3

$1.50 is a only a negligible difference due to rounding
$200 -> $205 when it should be $204.44
$1500 -> $1537.50 when it should be $1533.33

How can you trust either network to deliver is accurate news when they're unable to calculate a basic maths equation?

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Comment by carmenator, on 9-Feb-2010 20:57

Wow... hope you've contacted them both about it?

Comment by simon14, on 9-Feb-2010 21:07

What are you talking about?
The extra 2.5% added to GST is an extra $2.50 for every $100 you spend...
So spend $200 now will be $205 later
$1500 now will be $1537.50 later
TV3 got it right as far as i can see....

Comment by simon14, on 9-Feb-2010 21:09

oh wait a minute, now i actually read your post instead of just looking at the pic and I'm confused again!

Author's note by sbiddle, on 9-Feb-2010 21:22

You fell into the exact same hole they did

Comment by bcourtney, on 9-Feb-2010 21:39

The cynic in me suggests that most retailers will play on this confusion and increase their ticket prices (GST incl prices) by 2.5% rather than the 2.22% they should

Comment by Regs, on 9-Feb-2010 22:04

to quote TV3: "the cost of a $1.50" soft drink would only rise by 3.75 cents" while the figure on the screen is shown as "0.375 cents"

0.375 cents != 3.75 cents
0.375 dollars != 3.75 cents

so not only did they calculate the increase wrong, they transcribed their bad maths incorrectly.

Comment by kris, on 9-Feb-2010 23:13

looks they realised it

Comment by ejrg, on 10-Feb-2010 08:15

Just don't ask them to send a satellite to Mars.....

Comment by NonprayingMantis, on 10-Feb-2010 12:18

Well spotted there Regs.

classic fail on the decimal place there TV3.

0.375c increase is, to the nearest cent, no increase at all.

freakin retards

Comment by n4, on 10-Feb-2010 12:25

'$166.66 (rounded to 2 decimal places)' should be $166.67 :-D Glass house, stone, etc? Just kidding, good catch. I didn't notice at the time.

Comment by mozzle, on 10-Feb-2010 13:27

Steve, I think your final comment just said it all... "How can you trust either network to deliver is accurate news when they're unable to calculate a basic maths equation?" Well Spotted!

Comment by rscole86, on 10-Feb-2010 16:20

@n4 - If we are going to be picky... he never said which rounding he was using :P

I am sure the majority of NZers will not have noticed, and even after having it explained to them will a) not care b) still not understand c) a & b. Thats what I found at work anyway.

Comment by datacraft, on 10-Feb-2010 20:28

New Zealand's Media Motto: "Don't let the facts get in the way of a good story"

Comment by Quidam, on 11-Feb-2010 08:57

This is good spotting, but to be honest, doesn't seem to proove anything other than that their calculations were rushed and not properly Q/A'd

The fact is GST is going up, probably to 15%

The real debate is whether this is a good move by National, or whether there is a more equitable strategy available.

If it were me, I'd say luxury goods should be subject to higher GST content than items of necessity, thus ensuring people who absolutely "need" to buy that Porche GT3 give back more to the economy than those who are simply struggling to feed their families.

Comment by AndrewTD, on 11-Feb-2010 09:31

Well spotted Steve. Those news shows are becoming increasingly puerile, and now just plain stupid as well. They've got tot the point where they are in some respects providing the people a dis-service!
It's getting harder & harder to find accurate, "un-sensationalised" news content these days.This example just goes to show how much these 6pm news shows are far more entertainment based than "real" news.
Another beef I have is with the continuing decline of standards in spelling and grammar in the various forms of printed media.
(Having said that, it's now almost inevitable that someone will find a spelling or grammatical error in this post!)

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Steve Biddle
New Zealand

I'm an engineer who loves building solutions to solve problems.

I also love sharing my views and analysis of the tech world on this blog, along with the odd story about aviation and the travel industry.

My interests and skillset include:

*VoIP (Voice over IP). I work with various brands of hardware and PBX's on a daily basis
  -Asterisk (incl PiaF, FreePBX, Elastix)

  -xDSL deployments

*Structured cabling
  -Home/office cabling
  -Phone & Data

*Computer networking
  -Mikrotik hardware
  -WAN/LAN solutions

*Wireless solutions
  -Motel/Hotel hotspot deployments
  -Outdoor wireless deployments, both small and large scale
  -Temporary wireless deployments
*CCTV solutions
  -Analogue and IP

I'm an #avgeek who loves to travel the world (preferably in seat 1A) and stay in nice hotels.

+My views do no represent my employer. I'm sure they'll be happy to give their own if you ask them.

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