777, 888 and 999

You are given the numbers 777, 888 and 999. Using the numbers once and adding, subtracting, multiplying or dividing, how can you make 999?

(7 x 7 x 7) + (9 x 9 x 8) + ((9 – 8) x 8) = 999
(77 + 7) + 888 + (9 + 9 + 9) = 999

If other operators were allowed, another solution would be 999 modulo (888 x 777). I’m sure there are more solutions.

Posted in Brain Teasers

The Mysterious 6th Floor Window

A man was looking through a window on the 6th floor, opened it, thought for a minute then jumped, passing through the open window, but he was not injured. How was this possible?

He was a window washer and he was entering the building.

Posted in Brain Teasers

Making Lots of Shirts

In a textile factory, 5 machines take exactly 5 minutes to make 5 shirts. How many minutes will it take 100 machines to produce 100 shirts?

5 minutes. It takes each machine 5 minutes to make a shirt, so if you have all 100 machines running at the same time, they’ll produce the 100 shirts in 5 minutes.

Posted in Brain Teasers

Soft and Transparent

I am soft and transparent.
I am so small that I can sit on your finger.
I have no light but I help you to see the beautiful world.

What am I?

A contact lens.

Posted in Riddles
Tagged with

I Have Four Pairs of Letters

I have four pairs of letters,
Leaving two to stand alone.
You’re often doing the opposite,
When playing on your phone.

I help you get things done,
With one big caveat,
If taken to extremes,
I could make you fat.

What am I?

Efficiency. Being efficient helps you get things done, but if you’re extremely efficient with your tasks you get less exercise.

Posted in Riddles
Tagged with

First is Twice in Apple

My first is twice in apple but not once in tart.
My second is in liver but not in heart.
My third is in giant and also in ghost.
Whole I’m best, when I am roast.
What am I?

You are a pig.

Posted in Riddles

Ties One Another

What ties one to another and is closest to the heart?

A wedding ring.

I know, this is nearly a duplicate with What Holds Two People Together.

Posted in Riddles

In Oven But Not Baked

What must be in the oven yet can not be baked?
Grows in the heat yet shuns the light of day?
What sinks in water but rises with air?
Looks like sand, but is fine as hair?

Yeast.

Posted in Riddles

Two Three Ten Sequence

If:
2 3 = 10
7 2 = 63
6 5 = 66
8 4 = 96
9 7 = __

What is the missing number?

f(n, m) = (n + m) × n

e.g. f(2, 3) = (2 + 3) × 2 = 10

Hence, f(9, 7) = (9 + 7) × 9 = 144

Posted in Brain Teasers
Tagged with

The Bookworm

A bookworm eats from the first page of an encyclopedia to the last page in a straight line. The encyclopedia consists of ten 1000-page volumes and is sitting on a bookshelf in the usual order. Not counting covers, title pages, etc., how many pages does the bookworm eat through?

        __                             __
      B|  |                           |  |F
      A|1 |...........................|10|R
      C|  |                           |  |O
      K|  |                           |  |N
       |__|                           |__|T
      -------------------------------------

On a book shelf the first page of the first volume is on the “inside”, so the bookworm eats only through the cover of the first volume, then 8 times 1000 pages of Volumes 2 – 9, then through the cover to the 1st page of Vol 10 for a total of 8,000 pages.

Note: The question asks how many pages, not how many sheets of paper.

Posted in Brain Teasers