another probaility question plz help (1 Viewer)

[**blu_rose**]

the probability that saraj will pass next week's assessment is 90% and that carl will pass is it 60%.
what is the probabilty that:
b) carl will pass and sarah will fail
c)at least one of them will pass

b is supposed to be 3/50
c is spposed to be 24/25

how would u draw the tree diagram
and how to do the working out
plz plz help

 

[Jumbo Cactuar]

The two events are mutually exclussive.

For a:

probability carl will pass is; %60 = ³/₅
probability saraj will fail is; %100 - %90 = ¹/₁₀

probability carl will pass & saraj will fail; ¹/₁₀ x ³/₅ = ³/₅₀

For b:

'at least one of them will pass' is probably easier is you think it is %100 - probability both fail.

probability carl will pass is; %100 - %60 = ²/₅
probability saraj will fail is; %100 - %90 = ¹/₁₀

probability both fail is; ²/₅ x ¹/₁₀ = ¹/₂₅

'at least one of them will pass'; 1 - ¹/₂₅ = ²⁴/₂₅


For help on probility trees