BrainBashers™ is a collection of brain teasers & Japanese-type puzzles, optical illusions, and other fun stuff.
BrainBashers has items such as: Daily BB Words, logic puzzles, Sudoku, stereograms, magic games, memory games, mazes, typing tests, and so much more. Including a pointless box and a blank page!
puzzles
illusions
fun stuff
There is a wide range of things to do every single day. Take a look at the site map to see a list of everything, or perhaps choose a random page instead.
Daily Puzzle – Feb 17
At my local farmer's merchant, you can buy chicken feed for £4 per tonne, pig feed for £3 per tonne, and cattle feed for 40p per tonne. The feed can only be purchased by the tonne, and part tonnes aren't sold.
Last week I bought some animal feed, and luckily I managed to buy exactly 100 tonnes for exactly £100. How much of each feed did I buy?
Puzzle Copyright © Kevin Stone
workings
hint
answer
print
www.brainbashers.com
/puzzle/zwbr
share
Hint
What must the number of tonnes of cattle feed be a multiple of?
Answer
I bought 8 tonnes of chicken feed, 12 tonnes of pig feed, and 80 tonnes of cattle feed.
Reasoning
The number of tonnes of cattle feed must be a multiple of 5, because we need to have a whole number of pounds (5 x 0.40).
If all 100 tonnes was cattle feed, the cost would have been £40, which isn't enough.
If 95 tonnes was cattle feed the cost would have been £38, and the remaining 5 tonnes of (the most expensive) chicken feed at £20, gives a total of £58, which isn't enough.
If 90 tonnes was cattle feed the cost would have been £36, and the remaining 10 tonnes of (the most expensive) chicken feed at £40, gives a total of £76, which isn't enough.
If 85 tonnes was cattle feed the cost would have been £34, and the remaining 15 tonnes of (the most expensive) chicken feed at £60, gives a total of £94, which isn't enough.
If 80 tonnes was cattle feed the cost would have been £32, and the remaining 20 tonnes of (the most expensive) chicken feed at £80, gives a total of £112. So, this might be a possible answer …
We need 20 tonnes of chicken feed and pig feed to equal £68, so let's reduce the chicken feed until it works.
20 chicken + 0 pig = 80 + 0 = £80
19 chicken + 1 pig = 76 + 3 = £79
18 chicken + 2 pig = 72 + 6 = £78 …
We can see it's coming down 1 at a time, so we need to come down to a total of £68, which is 10 fewer tonnes of chicken feed:
8 chicken + 12 pig = 32 + 36 = £68. As required.
Double-Checking
8 x 4.00 = £32.00
12 x 3.00 = £36.00
80 x 0.40 = £32.00
--- ------
100 tonnes = £100.00
All daily items change at midnight GMT. set time zone
New And Updated Stuff
These items were new / updated in the last 14 days. I also have a more complete list of new / updated items.
Brain TeasersUpdated in the last 7 days. New / updated brain teasers twice a month.
Largest Area?New illusion in the last 7 days. Which of these shapes has the largest area?
