C. what is the implied tax (i.
e., tax/average income) on the highest quintile?

 The answer is derived from the top quintile LOSS of 101,800 which is due to taxes in other words this is the taxes paid. Therefore, the taxes paid divided by the average income of 170,000 or shown as 101,800/170,000 = .5988 which rounds to .60 or 60% implied tax rate. 

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post