Given
There are four defenders on a soccer team
if this represents 20 percent of the players on the team
Find out the total number of players on the team.
To proof
As given in question
four defenders on a soccer team
this represents 20 percent of the players on the team
let the total number of players = x
First convert 20% in the decimal form

Than the equation becomes
0.20x =4

now solving the above equation
we get
x = 20
thus the total number of players on the team are 20.
Hence proved
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%

I simply divided by 100 and moved the decimal two places to the left.