we know that
The probability that "at least one" is the probability of exactly one, exactly 2, exactly 3, 4 and 5 contain salmonella.
The easiest way to solve this is to recognise that "at least one" is ALL 100% of the possibilities EXCEPT that none have salmonella.
If the probability that any one egg has 1/6 chance of salmonella
then
the probability that any one egg will not have salmonella = 5/6.
Therefore
for all 5 to not have salmonella
= (5/6)^5 = 3125 / 7776
= 0.401877 = 0.40 to 2 decimal places
REMEMBER this is the probability that NONE have salmonella
Therefore
the probability that at least one does = 1 - 0.40
= 0.60
the answer is
0.60 or 60%
21/7=3mins per wall with 5 people.
Because we assume that all of the people paint at the same rate, 3 X 5=15 mins for one person working alone.
15/3=5 mins per wall with 3 people X 10 people= 50 mins for 3 people to paint 10 walls.
The answer is 50 mins.
If you imagine it like the picture below, you could use the pythagorean theorem to solve for x
1×5 or 5×1 would be a factual of it