Holiday work

This task is about ratios.
Joshua and Tamara both worked during their holidays.
Joshua earned less per hour than Tamara.
 
The ratio of Joshua's hourly earnings to Tamara's hourly earnings is 5 : 6.
 
a)
If Joshua earned $45, how much would Tamara earn in the same length of time?
 
$ __________
 
b)
If Tamara earned $90, how much would Joshua earn in the same length of time?
 
$ __________
 
c)
If Joshua and Tamara's combined earnings were $330 after they both worked for the same length of time, how much did Joshua earn?
 
$ __________