Chapter 2.2, Problem 6E

Given the $\text{1}000\times \text{ 1}000$ matrix A, your computer can solve the 500 problems $Ax=b_1,\mathrm{...},Ax=b_{500}$, in exactly one minute, using $A=LU$

factorization methods. How much of the minute was the computer working on the $A=LU$

factorization? Round your answer to the nearest second.