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If a goat is tethered with a 4.5m-long rope to the corner of a shed which is 2m long and 2m wide, what is the maximum area the goat can graze?
It is one of 15 questions recently answered by Otago Boys' High School pupil Pyo Kang in the 2014 Eton Press Senior Mathematics Competition.
The 17-year-old was one of hundreds of year 12 and 13 pupils nationwide who sat the examination, and he was excited to learn this week his result was inside the top 15.
''I was very surprised because I attempted the exam last year and I didn't do as well as I had hoped.''
This year's result will have him fly to Wellington in August where he will join the other pupils from the top 15.
They will sit another Eton Press examination to determine the top three placings.
''There is $1000 up for grabs,'' he said.
Pyo is studying NCEA level 3 calculus, statistics, physics, chemistry, computing and English this year, and hopes to study engineering in Singapore next year.
Given that he achieved high distinction in the international competitions and assessments for schools (ICAS) mathematics exam last year, Pyo is confident he can do well in the Eton Press final.
But when it came to giving assurances he could win some of the $2000 of prize money on offer, he said he was not counting all his goats yet.
In case you were wondering, Pyo said the goat could eat 57.3sq m - assuming it did not eat the tin shed first.