A bag contains $4$ red counters and $n$ blue counters. Two counters are selected at random witho

Question

A bag contains $4$ red counters and $n$ blue counters. Two counters are selected at random without replacement. The probability that both are red is $\dfrac2{15}$. Find $n$.[5]

Accepted Answer

$n=6$

Finding an unknown number of counters

Finding an unknown number of counters

Solution:

Solution locked