A computer spends 80% of its time executing user code and 20% of its time performing input/output operations. If you regard I/0 as an unn ecessary overhead, the efficiency of the computer is 80/(80 + 20) = 80%. 

Suppose that CPU performance is increasing at a compound rate of 40% per yea r and that the performance of I/0 systems is increasing at a compound rate of 10% per year. In another two years, a new computer can be bought with both faster processing power and I/0 performance. How efficient would the new computer be in two years' time?