Ten Green Bottles
Problem
Ten green bottles hanging on a wall
Ten green bottles hanging on a wall If one green bottle should accidentally fall There'd be nine green bottles hanging on the wall Nine green bottles ..... |
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If the first bottle fell at ten past five in the morning ($5.10$ a.m.) and the others fell down at $5$ minute intervals, what would the time be when the last bottle fell down? |
Getting Started
Think how many $5$ minutes are there between the first and tenth bottles falling.
Student Solutions
We had very clearly explained solutions to Ten Green Bottles. David from Tithe Barn Primary School, Stockport wrote:
The answer is that the last bottle fell at five minutes to six. I worked this out by writing down the numbers 1-10 and by the first number I put the time when it fell. Then, I added 5 minute intervals and put them at the next number down i.e. 5:10, 5:15, 5:20 etc.
Jeff from Kelly Elementary School in Carlsbad, California agreed with the answer of 5.55.
Airlangga from St Joseph's Catholic Primary School wrote:
5.10 + (5minx9) = 5.55
Alistair from Histon and Impington Infant School used a similar way of working it out to David, but then generalises, leading nicely on from Airlangga's response:
I have spotted that the equation for the nth bottle is 5 x(n-1) minutes after 5.10
Very well thought out all of you.