Random Puzzles 

Workings

Hint
28,121 isn't a prime number.

Answer
61 bags.

Reasoning
Each bag contains 461 carrots.

How do we find the correct answer? An easy way is to keep dividing 28,121 by the prime numbers in sequence until one works.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61.

Workings

Hint
You have to highlight three numbers.

Answer
6 + 1 + 12 = 19.

The puzzle didn't ask for three digits to be highlighted!

Workings

Hint
This question involves the months of the year in some way.

Answer
4 3 1.

Reasoning
This is the sequence of the length of the name of the month, and the number of days in that month.

7 3 1 = January, which has 7 letters, and 31 days.

8 2 8 = February, which has 8 letters, and 28 days.

5 3 1 = March, which has 5 letters, and 31 days.

5 3 0 = April, which has 5 letters, and 30 days.

3 3 1 = May, which has 3 letters, and 31 days.

4 3 0 = June, which has 4 letters, and 30 days.

Which means the next three digits are:

4 3 1 = July, which has 4 letters, and 31 days.

Workings

Hint
What could we do with the digits?

Answer
If the sum of the digits is divisible by nine, so is the number.

Add up all of the digits in the number and see if the sum is divisible by 9. If you still can't tell, you can add those digits again to see if the new sum is divisible by 9. You can keep going until you the sum is obviously divisible by 9 or not.

For example, is 486451464 divisible by 9?

Do 4 + 8 + 6 + 4 + 5 + 1 + 4 + 6 + 4 = 42.

Is 42 divisible by 9? Not sure, you can then do:

4 + 2 = 6. Which clearly isn't divisible by 9. So our original number, 486451464, isn't either.