Mukul Kandpal

Second approach would be better because in first scenario only initial cost will be low however probability of getting results intially is also only 50%. Post that with every added sample cost will increase (and timeline also increases with each step) and probability of success in each step will remain 50% unless and until final results are achieved. Whereas if we select second option then initial cost might be bit high but probability of getting results is 100% which will save cost and time both. And time becomes more critical depending upon the process. So my answer will be second one.