Easy maths problems.......

[gibsr]

1. A bag contains 5 white balls, 3 blue balls and 2 green balls. Each time a ball is drawn from the bag, it is not replace. In three draws find the probabilityof obtaining white, blue and green balls in that order.


2. Four machines - an excavator, a dumper truck, a scraper and a crane operate independently of each other. The percentage of time they are utilised are

Excav = 50%
Dumper = 40%
Scraper = 70%
Crane = 30%

i) Determine the chance of the excavator and the dumper truck not being used at any interval of time.

ii) Calculate the chance of all machines being busy.

iii) Calculate the chance of all machines being idle.

[sevenhalo]

There's always a 100% of getting blue balls.

Is this homework?

[gibsr]

Got an A-level maths paper to do as coursework. Cant do these questions...my maths is hopeless. Im doing a degree aswell

[bilm_ks]

1. P(w,b,g) = 1/2*3/9*2/8 for one draw. Suppose that you replace the balls for the next draw (otherwise the prob is 0, there are only 2 green) the probability for 3 draws is P(w,b,g)^3
2.
i) P(Excav and Dumb) = P(E ^ D) = P(E)*P(D) = 50/100 * 40/100
ii) P(all) = P(E ^ D ^ S ^ C) = 50/100 * 40/100 * 70/100 * 30/100
iii) 1 - P(all)