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?
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.
Reasoning
This is the only word that cannot be spelled using a calculator.
For example, if you enter 376616 into an old-fashioned calculator, and look at the number upside down, you can read GIGGLE.
376616 = giggle
7105 = soil
57738 = bells
378806 = gobble
4506 = gosh
5508 = boss
3704 = hole
5355378 = blesses
coil = N/A
??
Puzzle 4
Hidden in the grid below are eight, 7-letter words. Each word begins with the central P and you can move one letter in any direction to the next letter. All of the letters are used exactly once each. What are the words?
D
I
S
I
S
A
K
M
R
C
N
C
Y
E
A
C
Y
A
H
N
A
H
Y
S
P
I
B
L
I
E
R
O
L
L
S
C
M
P
U
R
A
T
M
U
I
L
A
E
R
Note: this puzzle is not interactive, and the letters cannot be clicked.
