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EACH DAY THIS week we’ve been entertaining – or torturing – you with a maths teaser.
We haven’t been doing it out of sheer cruelty – all this week, libraries, colleges, universities and other groups have been running events to highlightmathsweek.ie and the practical benefits of basic numeracy skills to our everyday life.
And here are the answers you’ve been waiting for. Let us know how you did…
Monday’s puzzle: A cash collection was made around a room with everyone putting a note into a bag. People put in either a €20, a €10 or a €5 note.
I asked the collector how much was in the collection and he told me that if I pulled out a note at random that there would be a 1 in 12 chance of getting a €20 note. He said there would be a 1 in 4 chance of getting a €10 note and a 2 in 3 chance of getting a €5.
I protested that I needed more information. He conceded that four people had put in €20 notes and he refused to tell me any more.
Can you figure out how much money was in the bag?
The choices were:
€255
€360
€280
€325
Answer: €360
Tuesday’s puzzle: A teacher did a little survey of the pets her pupils had.
Half the children had a dog each and there were three times as many dogs as cats, three more goldfish than cats and two hamsters.
Wednesday’s puzzle: You are travelling to Britain and you change €500 into Sterling. The exchange sells you Sterling notes at 0.76 £/€ and takes a £2 commission.
On your trip you spend half your Sterling, and when you return you change it back to euro at 0.79 £/€ and the exchange takes €3 commission.
How much are you left with in Euro?
The choices were:
€295.62
€240.51
€256.08
€236.24
Answer:€236.24
Thursday’s puzzle: I realised that I take around 60 seconds to brush my teeth and I’m in the habit of leaving the tap running. I measured that the tap will fill a 2 litre jug in 16 seconds. I decided to just allow the water to flow while I was rinsing the brush and my mouth. I could accomplish this in 10 seconds.
Assuming that I brush my teeth twice a day at home, how much water will I save in a year?
The choices were:
3,874.75 litres per year
2,757 litres per year
3,230 litres per year
4,562.5 litres per year
Answer: 4,562.5 litres = 4.56 m³
Friday’s puzzle: I found a piece of paper with the following list of numbers on it. The end of the note was torn off. What do you think the next number should be?
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And just how do they construe a situation whereby they have “depleted reserves” ……..what with all the rain lately and it also being a time when lots of visitors are expected to the islands you’d think……..awe. ….maybe not!
we were over that way last week staying in Doolin, it rained most of wednesday, hammered it down on thursday and didnt stop at all on friday , in fact the rain was that heavy the river went from being a couple of inches deep to nigh on 3 -4 ft deep by friday night . and it was all coming in from a seaward direction i.e. from over the islands.
Eric, across the bay in Sunny Spiddal, about 28km as the crow flies, Wednesday and Thursday were glorious days, albeit it did piss on Friday.
Dermot Ryan is correct, the Aran Islands and indeed quite a bit of coastal Connemara, experience less rainfall hours than most parts of Ireland. The annual insolation in these areas is on a par with Wexford.
Odd that reserves are low on Inis Oirr. They got a new lake recently that should have catered for demand. Restrictions are 8pm to 8am so its not too bad
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