maths en anglais ! ! !

a box contains sweetes of different colours : orange, blue, red and yellow . Duncan is going to choose one sweet at random from the box . The table shows each of the probabilities that Duncan will choose an orange sweet, a red sweet or a yellow sweet .

orange = 0.35 red = 0.24 yellow = 0.19

1) work out the probability that Duncan :

a) will choose a blue sweet

b) will not choose a red sweet

2) the box contains 250 sweets . estimate how many red sweets are in the box

1

Réponses

2014-10-22T18:51:38+02:00
1. The sum of the probabilities is 1 : thus prob(orange) + prob(yellow) + prob(red) + prob(blue) = 1 
Just solve the equation prob(blue) = 1 - (orange + yellow + red).
2. prob(red) = 0.24 so prob(not red) = 1 - 0.24 
3. I have no doubt that you can do it alone :) 

Answered in english, if you have issues to understand, contact me by PM, will explain it in french.
Il ne te reste plus qu'à résoudre l'équation
j ai trouvé qu il y avait 0.22 bleu
j ai trouvé 0.76 rouge
j ai trouvé 20 rouges dans la box
merci