Math
posted by Sarah .
A bag holds 8 yellow marbles and 5 orange marbles. How many and what color marbles would you add to the bag so that the probability of picking a yellow marble is 2/3?

Math 
Reiny
lets add x yellow marbles
so (x+8)/(x+13) = 2/3
3x + 24 = 2x + 26
x = 2
must add 2 yellows
or
lets add y orange marbles
8/(y+13) = 2/3
2y + 26 = 24
2y = 2
y = 1
or we could take out 1 orange marble
Proof:
yellow = 8
orange = 4
total = 12
prob of yellow = 8/12 = 2/3
Respond to this Question
Similar Questions

math
A bag holds 8 yellow marbles and 5 orange marbles.How many and what color marbles would you add to the bag so that the probability of picking a yellow marble is 2/3 
Math
There are 150 green marbles and 100 yellow marbles in a bag that contains 250 marbles. If only yellow marbles are added to the bag so that the probability of randomly drawing a yellow marble from the bag becomes 3/5, how many yellow … 
math
A bag holds 3 yellow marbles and 7 blue marbles. how many and what color marbles could you add to the bag so that the probability of picking a yellow marbles is 1/4? 
math
A bag holds 8 yellow marbles and 5 orange marbles. How many and what color marbles could you add to the bag so that the probability of picking a yellow is 2/3? 
Math
Bobby has a bag of marbles with nine red marbles, 13 yellow marbles and six orange marbles. He picks one marble and keeps it out. He wants to find the probability of picking a yellow marble by randomly picking one more marble from … 
math
A bag has 6 green marbles and 4 orange marbles.Find the least number of marbles of either color you would add to make the probability of picking an orange marble 
Statistics
A bag contains 5 purple marbles, 7 yellow marbles, and 3 orange marbles. If two marbles are selected from the bag: What is the probability that an orange then a yellow are chosen with replacement? 
GEOMETRY
A bag contains 3 yellow marbles, 4 green marbles, 6 purple marbles, and 2 orange marbles. If a marble is drawn from the bag, what is the probability that it is orange? 
math
There are 12 marbles in a bag, and the marbles are either yellow or green. Two marbles will be randomly picked from the bag, without replacing the first one picked. The probability that both marbles will be yellow is 5 33 . How many … 
STATISTICS
A bag contains 5 purple marbles, 7 yellow marbles, and 3 orange marbles. If two marbles are selected from the bag: What is the probability that a yellow then an orange are chosen without replacement.