Tuesday, February 9, 2010

Buying Flowers

Knightmare decides to buy his couch some flowers for Valentines Day ... (hmmm ... must be the little voices he hears ... oh well). Thinking it is tea, he accidentally consumes a large quantity of bourbon ... then heads to the florist.

He buys x number of flowers for y dollars (x and y are integers). As he staggers ... ooops, I mean walks away from the counter, after paying, the clerk says "If you buy ten more flowers, I will give you all for $2.00, and you will save $.80 a dozen". (the little voice says "don't do it").


How many flowers will Knightmare present to his lovely couch on Valentines Day? ... and how much did he spend?

8 Comments:

Anonymous Carc said...

i would say he bought 60 flowers for $124

February 9, 2010 8:12 AM  
Blogger Zulfiqar Malik said...

He bought 50 flowers @ $3.2/dz. Makes it $160 in total

February 9, 2010 8:25 AM  
Anonymous Carc said...

but that can't make sense..
with 10 more flowers he would had 60 and because 1 would cost $2 then the total price would be $120, which is less than for 50 flowers, so the seller must be very stupid

February 9, 2010 8:37 AM  
Anonymous Rachel said...

he bought one dozen for $2.00 instead of one dozen @ $3.20 (he had 2 flowers plus the ten to make it one dozen @ $3.20 - the .80 cent discount for total of 1 dozen for $2.00

February 9, 2010 10:23 AM  
Blogger Zulfiqar Malik said...

To me it seems that the shopkeeper means that he will give him the rest of 10 for $2.
Reducing overall price will obviously get him cheaper, no matter what numbers you put in. The numbers are a way of making calculations back to the original price so:

10 flowers = $2 + $.80 (before discount)
Hence rate = $3.2/dozen
Also the number of flowers + 10 must be divisible by 12 and the total cost must be integral.
A bit of maths tells me that such a number is 50 since (50 + 10)/12 = 5 and also 5 * 3.2 is a round number. There can be other solutions as well but this is the least number according to my calculations.

February 9, 2010 10:26 AM  
Anonymous Anonymous said...

i meant 2.80 instead of 3.20

February 9, 2010 10:48 AM  
Blogger Zaux said...

Hi Zulfiqar ...
you are right ... he bought 5 flowers


Since y is an integer < 2, y = 1. Then, dealing with price per flower in cents,

100/x + 200/(x+10) = 80/12 or
x^2+25x-150=0

of which the positive root is x=5, the number of flowers originally purchased.

February 9, 2010 10:56 AM  
Blogger Zaux said...

oops ... error above

should be:

100/x - 200/(x+10)= 80/12

February 9, 2010 11:19 AM  

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