HOME

TREATISE:
. Quantum
Nodal Theory

ROMALDKIRK:
. Village
. Reservoirs

ESSAYS: COSMOLOGY
. Infinity
. Universe
. Dark Matter

ESSAYS: PHILOSOPHY
. Free Will
. Representation
. Conditionals
. Postscript

ESSAYS: ORGAN MUSIC
. Practising
. British Organs
. Hymn Playing
. Music Lovers

QUIZ QUESTIONS
. Quiz Archive

SERVICES
. Book Reviews

## Quiz of the Month (March 2005)

### Hector C. Parr

***

#### SOLUTION TO LAST MONTH'S QUIZ

```   1.  48 ml.
2.  30 mpg.
3.  32.4 mpg.```

Notes
```  Suppose fuel used before start  = x gal.
and fuel used for each 20 ml of journey = y gal.

So distance travelled before start = 36x ml.
So   (36x+20)/(x+y) = 34
and (36x+40)/(x+2y) = 33

Solving:  x = 1 1/3, y = 2/3

So:   1. Distance = 36x = 48 ml
2. mpg = 20/y = 30
3. Reading = (36x+60)/(x+3y) = 32.4 mpg```

#### THIS MONTH'S QUIZ

The sock-drawer in my bedroom contains 8 black socks, 6 grey ones and 2 brown ones. Just as I am about to select a pair, the light fails and the room is plunged into darkness.

1. If I pick out two socks at random, find the probability that they form a matching pair.

2. If I pick out three socks at random and take them into a lighted room, find the probability that they include a matching pair.

3. If I pick out four socks at random and take them into a lighted room, find the probability that they include at least one matching pair.

***