# Discuss and Choose

##### Stage: 1 and 2 Challenge Level:

Some good suggestions came to us from pupils from many different countries. The answers I used were from a Nature Statistics web site. Mya from Ricards Lodge High School, UK sent in the following ideas for number $7$. She showed a good use of animal knowledge and of mathematical skills.

I think that I might have a solution for number $7$.
The question is ... Adult elephants need to drink about $100$/$200$/$400$ litres of water a day. I think that it is ... $100$l.
An average adult human should drink about $2$ litres of water a day (coffee and tea don't count). An average ADULT human weights about between $65$/$80$ kg. So the median of the two numbers is $78$, so it should be approximately $1$l per $39$ kg ($39$ is half $78$), for a human.
So bearing that in mind if an average adult elephant however weights $4.6$ tons, so converting that into kg that would be $4600$kg.($1$ ton is equal to $1000$kg.)  So that is more than $70$ times more than an average human weight ... because $65x70$ would give you $4550$kg - only $50$kg short of $4600$kg.
So if you multiply that by $70$ then multiply the amount of water (litres) by $70$ ... so you would get $140$.  Rounding it to the nearest hundred you get $100$l !!
I think that is right.

Ella, from the same school, sent in these answers:

$1) 500$ million
$2) 4.5$kg
$3) 13-14$ hours
$4) 400$ million
$5) 10-14$ years
$6) 20$ individuals
$7) 100$ litres
$8) 170$cm
$9) 5$ times as thick
$10) 180$kg
$11) 8$km
$12) 20$ hours

Aadil from Riverside Primary School, UK sent in these good suggestions as answers, many of which were correct:

$1$. $500$ million
$2$. $4.5$kg
$3$. $18-19$ hours a day
$4$. $600$ million
$5$. $10-14$ years
$6$. $30$ individuals
$7$. $200$ litres
$8$. $170$ cm
$9$. $5$x
$10$. $250$kg
$11$. $16$km

Betina, Luiza and Katrina from the British School in Barra, Brazil sent in these solutions, written here in the same order as their names:

$1$ $500, 500, 500$
$2$ $4.5, 4.5, 4.5$
$3$ $13-14, 13-14, 13-14$
$4$ $600, 400, 400$
$5$ $18-20, 10-14, 10-14$
$6$ $12, 12, 12$
$7$ $400, 200, 200$
$8$ $220, 170, 170$
$9$ $5, 10, 10$
$10$ $330, 250, 250$
$11$ $8, 8, 8$
$12$ $15, 20, 20$

We also had answers from Germain, Mount Zion School, U.S.A., Julia from TromsØ
School in Norway and Harry and Fin from Jebel Ali School in U.A.E.

The answers that I used to set the challenge were:

$1) 500$

$2) 4$ to $5$

$3) 13$ to $14$

$4) 400$

$5) 10$ to $14$

$6) 12$

$7) 200$

$8) 170$

$9) 10$x

$10) 180$

$11) 8$

$12) 20$