Brain Teasers and Puzzles 

Workings

Hint
How many days separate the two dates?

Answer
18 days.

The second date (Date2) occurs 140 days after the first date (Date1).

If we temporarily ignore the 50 day gap, we therefore have 90 days to split in the ratio 4:1, which is 72:18.

So we have Date1 -> 72 days -> 50 days -> 18 days -> Date2.

18 days before Date2 is 30th July.

Workings

Hint
Look at the last letters.

Answer
Steve.

The last letters are in alphabetical order.

Workings

Hint
A little algebra might help.

Answer
1/8.

If we convert the question to algebra we have:
((n^2 + 4) x 2 - 3) x 4 - n = 20

Expanding the brackets and simplifying gives:

(2n^2 + 8 - 3) x 4 - n = 20

    (2n^2 + 5) x 4 - n = 20

         8n^2 + 20 - n = 20

              8n^2 - n = 0 (*)

                    8n = 1

                     n = 1/8

In the equation marked (*) zero is also a potential solution, but as the question tells us that we "Start with a number larger than 0" we know that n can't be 0, and therefore we can safely divide by n.

Workings

Hint

Answer