Ok, im going to make some assumptions and say this should read:
Sandra earns $164 for working 16 hours and $512.50 for working 50 hours. The relationship between her income and the number of hours worked is what rate?
Doing some quick math you find:
$164/16hours = $10.25/hour
$512.50/50hours = $10.25/hour
This problem seems fairly straight forward and I would say Sandra earning rate is $10.25 per hour. Apparently she is not paid for overtime.