urgent help

Suppose a program task takes 3 billion instructions to execute on a processor running at 4.2Ghz. If 15% of the instructions execute in 4 clock cycles, 10% in 2 clock cycles, 30 % in 3 clock cycles and 45% in 1 clock cycle, what is the execution time for the program task?

Suppose the process from above is changed so that all instructions that initially executed in 3 clock cycles now take 1 clock cycle. Those that took 4 clock cycles now take 3 clock cycles. In addition the clock rate is increased to 4.6Ghz. What is the new execution time? \begin{tabular}{c} \hline 1.403 secs \\ \hline .7932 secs \\ \hline 1.5536 secs \\ \hline .9130 secs \end{tabular}