We are asked to determine which games have a 1/7 chance of winning. -
In the case of Roseanna's game, we have that there are 5 red blocks and 30 blues blocks. If the winner is the person that pulls out a red block then to determine the probability we must determine the quotient between the number of red blocks and the total number of blocks, like this:
[tex]P(red)=\frac{5}{5+30}[/tex]Solving the operations:
[tex]P(red)=\frac{5}{35}=\frac{1}{7}[/tex]Therefore, Roseanna's game has a 1/7 probability.
In the case of Kennedy's game, there are 1 red block and 7 blue blocks, therefore, the probability of getting a red block is:
[tex]P(red)=\frac{1}{7+1}=\frac{1}{8}[/tex]Therefore, Kennedy's game has not a chance of 1/7 but 1/8 of winning.
For Kennedy's game to have a probability of 1/7 he could remove one of the blue blocks, that way the probability is:
[tex]P(red)=\frac{1}{6+1}=\frac{1}{7}[/tex]In the case of Guadalupe's game, we have that there is a dice with 7 sides numbered from 1 to 7. This means that the probability of getting a 3 is:
[tex]P(3)=\frac{1}{7}[/tex]Therefore, Guadalupe's game has a probability of 1/7.