To determine the probability that exactly two of the five marbles are blue, we will use the rule of multiplication.
Let event A = the event that the first marble drawn is blue; and let B = the event that the second marble drawn is blue.
To start, it is given that there are 50 marbles, 20 of them are blue. Therefore, P(A) = 20/50
After the first selection, there are 49 marbles left, 19 of them are blue. Therefore, P(A|B) = 19/49
Based on the rule of multiplication:P(A ∩ B) = P(A)*P(A|B)P(A ∩ B) = (20/50) (19/49)P(A ∩ B) = 380/2450P(A ∩ B) = 38/245 or 15.51%
The probability that there will be two blue marbles among the five drawn marbles is 38/245 or 15.51%
We got the 15.51% by dividing 38 by 245. The quotient will be 0.1551. We then multiplied it by 100% resulting to 15.51%
Let the amount of shells collected by Aaron be
and the amount of shells collected by Maria be
respectively. Then the following system of equations should be solved:
First of all, express
out of first equation:
Then, replace
in second equation with found expression and solve it:
Finally, replace
in first equation with found value and solve it too:
So, Aaron has found
7 shells while Maria has found
21.
I think its 11 for its absolute value
She is correct because a negative subtracted by a negative is positive.
