As Maths Probability,

Can anyone help check if the answers I did for these were right as I don't currently have access to a mark scheme for this.
I) 0.3×0.4×0.2 = 0.024
ii) 1-probabilities = 0.7, 0.6, 0.8
0.7 × 0.6 × 0.2 = 0.336
iii) 0.3 + 0.4 + 0.2 = 0.9
0.3/0.9 = 1/3

1 and 2 look good

For 3, you've added up all the probabilities of them being late and then taken Geoff's one and made a fraction but it doesn't seem to follow.

Remember that if only Geoff is late, then the others are not late.

So would it be 0.2 × 0.7 × 0.6? Thank you