(a) Translate the following odds to ‘probabilities’: 13/8, 2/1 on, 100/30.

(b) In the 2.45 race at Plumpton on 18/10/94 the odds for the five runners were:

Philips Woody ................................ 1/1
Gallant Effort .................................. 5/2
Satin Noir ..................................... 11/2
Victory Anthem .............................  9/1
Common Rambler ......................  16/1

Calculate the ‘probabilities’ and their sum.

(c) Should the bookmaker base his odds on the true probabilities of each horse winning, or on the amount bet on each horse?