(a)[2]
Complete the tree diagram by filling in the missing values.
(b)[2]
The probability of drawing two white balls is $\frac{1}{15}$. Show that $n^2 - n - 90 = 0$.
(c)[2]
Find the value of $n$ exactly.
Mathematics 4024 · O Level · Probability of combined events
Probability of combined events — practice question
A bag contains $n$ balls. 3 of the balls are white. Two balls are selected at random from the bag without replacement.