The first thing you would need to do is multiply the first 40 hours by 7.80, the payrate, this will get you 312. We know she makes a total of 352.95, so we subtract the amount of money she made from the first 40 hours from 352.95, getting us 40.95. We know that after these 40 hours, she receives an additional 3.90 in her payrate, we add 7.80 to 3.90, getting 11.7. We now divide 11.7 from 40.95 to get the additional amount of ours she worked after the first 40, we get 3.5. We now add 3.5 to 40, getting us 43.5.