ATAR Notes: Forum

VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: nacho on September 18, 2011, 09:17:06 pm

Title: Probability Question
Post by: nacho on September 18, 2011, 09:17:06 pm

Straight out of mathsquest:

"If Pr(A) = 4 Pr(B), Pr(A U B ) = 0.8 and Pr(intersection A, B) = 0.2
find Pr(B)
and Pr(A)"

im guessing Pr(A) = 4 Pr(B) means 4 times pr(b) ?
okay im an idiot, nvm i got it :D

Title: Re: Probability Question
Post by: REBORN on September 18, 2011, 09:26:20 pm

yeah so Pr(A) = 0.2?

Title: Re: Probability Question
Post by: nacho on September 18, 2011, 09:28:27 pm

Quote from: ssNake on September 18, 2011, 09:26:20 pm

yeah so Pr(A) = 0.2?

Pr(B) = 0.2, i think thats what you mean? :P

Title: Re: Probability Question
Post by: REBORN on September 18, 2011, 09:30:46 pm

yep. -.-

Let Pr(B) = x

0.8 = 4x + x - 0.2
0.8 = 5x - 0.2
5x = 1
x = 0.2