Let required burst time per process = x
Waiting time for a process = 30% of x = $\frac{30}{100} $ x= $\frac{3}{10}$ = 0.3 x
if all operations are not overlapped then
total waiting time = no.of processes * Waiting time for a process = 5 * 0.3x = 1.5 x
total required time (cpu usage + waiting time) = 5x + 1.3 x
if all operations are overlapped then (assuming running operations also overlapped)
total waiting time = Waiting time for a process = 0.3x
total required time (cpu usage + waiting time) = x + 0.3 x
probability of CPU time utilized is ( all operations are overlapped )= $\frac{x-0.3x}{x+0.3x} $ = $\frac{0.7 x}{1.3x} $ = $\frac{7}{13} $