Answer:
a ) ,
b )
Step-by-step explanation:
This is a nice and short question we have here.
Given that a bag has n counters, and that one counter is blue, respectively the rest is red, if two counters are taken at random there isn't a definite percentage that one of the counters chosen is red or blue, but there is a fractional representation of this.
We could express n ( number of counters ) to form a probability of 2 / n. As you can see, two counters are taken at random over n counters, and thus we derived this fraction.
a )
____
Now we have this second part -
Therefore, there are 15 red counters. Hope that helps!