Random Puzzles 

Workings

Hint
What are the maximum and minimum tonnes of pig feed I could have bought?

Answer
I bought 15 tonnes of chicken feed, 75 tonnes of pig feed, and 10 tonnes of cattle feed.

 15 x 0.15 =    2.25
 75 x 1.25 =   93.75
 10 x 0.40 =    4.00

100 tonnes = $100.00

A possible solution method follows …

I couldn't have bought 80 tonnes of pig feed because this would have cost the full $100.00, but I wouldn't have then had 100 tonnes in total.

Similarly, 70 tonnes of pig feed would have been too few, as this would cost $87.50 and even the remaining 30 tonnes all being cattle feed wouldn't have reached the required $100.00.

So, let's try 71 tonnes of pig feed = $88.75:

   plus 1 x chicken feed + 28 x cattle feed is over $100.00
   or   2 x chicken feed + 27 x cattle feed is under $100.00

   so 71 tonnes of pig feed doesn't work.

Let's try 72 tonnes … and so on.

We soon get to 75 tonnes of pig feed and find the answer.

Workings

Hint
In the first box, look at 7 & 3, and 4 & 1, to see how we can use them to make 12.

Answer
4.

Reasoning
For each row, the left minus the right gives a number.

The numbers for the rows are then multiplied together.

In the first box:

   7 – 3 = 4
   4 – 1 = 3

so 4 x 3 = 12

In the second box:

   9 – 2 = 7
   8 – 3 = 5

so 7 x 5 = 35

In the last box:

   6 – 2 = 4
   8 – 7 = 1

so 4 x 1 = 4.

Workings

Hint
Work out the total number of legs.

Answer
23 children (46 legs).

With 230 ants (1380 legs), 3 puppies (12 legs), and 1 teacher (2 legs).

If we call the number of puppies P, then there were (P + 20) children and 10 x (P + 20) ants, and a single teacher. If we now count the legs, we get:
Puppies:
 P x 4 =  4P

Children:
 (P + 20) x 2 =  2P + 40

Ants:
 10 x (P + 20) x 6 = 60P + 1200

Teacher: 2

A total of 66P + 1242

Giving:

 66P + 1242 = 1440

 66P        = 198

   P        = 3

So there were 3 puppies, hence 23 children.

Workings

Hint
The of words are all fruits.

Answer
Banana, apple, pear, and mango.