About how long does it take to solve 10 sets of 1000 linear equations
in 1000 variables, with the same coefficient matrix but different
righthand sides, using a computer with a speed of 5 G Flops/sec?

1000 seconds
Incorrect.

100 seconds
Incorrect.

10 seconds
Incorrect.

1 second
Correct!

0.1 second
Incorrect.

0.01 second
Incorrect.