There are only red counters, yellow counters and blue counters in a bag.
Kevin takes at random a counter from the bag. He puts the counter back in the bag. Lethna takes at random a counter from the bag. She puts the counter back in the bag.
The probability that both counters are red or that both counters are yellow is 13/36.
The probability that the first counter is red and the second counter is not red is 1/4.
Seb takes at random a counter from the bag.
Work out the probability that Seb takes a yellow counter.
So far, from the text, I've formed $2$ equations but since the number of unknowns is greater than the number of equations, I cannot solve.
$[(R^2)/(R+Y+B)^2] + [(Y^2)/(R+Y+B)^2] = 13/36$
$[(R)/(R+Y+B)]*[(Y+B)/(R+Y+B)] = 1/4$
Any help would be appreciated. Thanks.