Correct. The probability that the second ball is black (given that the first ball is striped) is $\displaystyle\frac{{10}}{{29}}\usepackage{cmbright}\Huge\$ and the probability the second ball is white (given the first ball is striped) is $\displaystyle\frac{{15}}{{29}}\usepackage{cmbright}\Huge\$ . Add these probabilities to get the probability the ball will be either black or white: $\displaystyle\frac{{10}}{{29}}+\frac{{15}}{{29}}=\frac{{25}}{{29}}\usepackage{cmbright}\Huge\$ .