Ten boys and girls write their names on slips of paper-one name per slip-to enter a prize drawing. Two of the names are drawn at random without replacement. If the probability that both winners are boys is $\frac1{15}$, how many boys are in the group?
I started off by noting that there are $10$ people in total, and tried multiplying it with $\frac1{15}$ and I got that there were $\frac{2}{5}$th but that's not possible, please help. thank you.