Question

HELP PLEASE AND THANK YOU!! Two sisters, Julia and Anna, both trade stocks online to supplement their pensions. In 2015 Julia earned $20,000 more than Anna from her trading. For 2015 neither of them reported their investment income to the Canada Revenue Agency. In 2016 Julia made $30,000 more from trading than she had the year before, and Anna made $10,000 more than she had the year before. For 2016 both declared their trading income and paid 50% of it in tax. Their combined income after tax from trading in 2016 was $80,000. How much did Julia make from trading in 2015?

Answer 1

Suppose Julia made x dollars in 2015, and Anna made y dollars.
in 2016, Julia made (x+30,000) and Anna made (y+10,000)
In 2016, after they paid 50% tax, they still had 80,000, which means before tax they had a total of 160,000, so
(x+30,000)+(y+10,000)=160,000
simplify: x+y=120,000
in 2015, Julia earned 20,000 more than Anna, so x=y+20,000. Plug it in the above equation: y+20,000+y=120,000
y=50,000
x=y+20,000=70,000
Julia made 70,000 dollars in 2015.