There are 52 weeks in a year and if she gets paid every two weeks then divide 52 by 2 to get 26 so she would get paid 26 times a year so divide her annual salary by 26 to get $1,346.15 every other week. So her biweekly salary is $1,346.15.
To get a close estimate, we can round 49 up to 50 and 311 down to 300, obtaining an estimate of 50/300 = 1/6, or 0.1666... as a repeating decimal. That decimal approximation is a little less than one hundredth away from the actual decimal approximation of ≈ 0.1576