Simultaneous equations without algebra ?

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QUEENMA
Posts: 132
Joined: Fri Feb 20, 2009 3:05 pm

Simultaneous equations without algebra ?

Post by QUEENMA »

Dear All
I am confused about how to solve the following problem without using simultaneous equations or algebra.How do you explain the method to a 10 year old ?

1 banana and 1 pear cost 21 p ; 3pear and 2 bananas cost 54 p

What is the cost of 1 pear ?

Please help us !

Queenma
999 mum
Posts: 422
Joined: Sun Feb 14, 2010 12:02 am

Re: Simultaneous equations without algebra ?

Post by 999 mum »

QUEENMA wrote:1 banana and 1 pear cost 21 p ; 3pear and 2 bananas cost 54 p

What is the cost of 1 pear ?
1 banana and 1 pear = 21p

so 2 bananas and 2 pears = 42p

3 pears and 2 bananas = 54p take away the 2 bananas and 2 pears equals 1 pear

so 1 pear =54p - 42p

1 pear = 12p
QUEENMA
Posts: 132
Joined: Fri Feb 20, 2009 3:05 pm

Re: Simultaneous equations without algebra ?

Post by QUEENMA »

wow - thanks 999mum !

that was great - simple and quick !

Queenma

PS: May I ask, did you just figure it out or are there some strategies for these kind of sums that one must know - I do feel quite 'unintelligent' with some of these questions !
WP
Posts: 1331
Joined: Thu Jan 03, 2008 9:26 am
Location: Watford, Herts

Re: Simultaneous equations without algebra ?

Post by WP »

In fact 999mum used the standard simultaneous equation method, but she did it so smoothly you didn't notice. The first step was to manipulate one or both of the given pricings so that they both had the same number of bananas. Once you've done that, you can subtract one pricing from the other and the resulting pricing only involves pears, not bananas.
no_ball

Re: Simultaneous equations without algebra ?

Post by no_ball »

after this step introduce gentle algebra is not so bad. Call it B and P, make either B or P the subject of the equation and out pops the answer.
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