Mathematical Puzzles 

Workings

Hint
A baker's dozen is usually 13.

Answer
Hours in a week.

Reasoning
A dozen is 12, but a baker's dozen is usually 13.

So a dozen (12) baker's dozen (13) = 12 x 13 = 156.

There are 24 hours in a day, and 7 days in a week.

So there are 24 x 7 hours in a week = 168.

Workings

Answer
49 tonnes of chicken feed, 46 tonnes of pig feed and 5 tonnes of cattle feed.

Workings

Hint
The answer involves multiplication (for example, 9 x 8 = 72).

Answer
468.

Reasoning
If we split each line in the following way:

98 68 88
72 48 64
14 32 24

Each new line is generated by multiplying the digits two at a time and writing the result below.

For example, 9 x 8 = 72, so 72 appears directly below 98.

And 7 x 2 = 14, so 14 appears directly below 72.

Double-Checking
9 x 8 = 72, 7 x 2 = 14, 1 x 4 = 4.

6 x 8 = 48, 4 x 8 = 32, 3 x 2 = 6.

8 x 8 = 64, 6 x 4 = 24, 2 x 4 = 8.

Workings

Hint
There are 60 seconds in a minute, and 60 minutes in an hour.

Answer
Seconds in a week.

Reasoning
There are 60 x 60 x 24 x 7 = 604,800 seconds in a week.

There are 60 x 24 x 365 = 525,600 minutes in a (non-leap) year.