After 2.0 years, the 4.0 mg sample decays to 2.0 mg.
After another 2.0 years (total 4.0 years), the 2.0 mg sample decays to 1.0 mg.
And after another 2.0 years (total 6.0 years), the 1.0 mg sample decays to 0.50 mg.
So it takes 6.0 years for 4.0 mg to decay to 0.50 mg.
Sorry don't know explane the question
Putting the value of Y = 15
So, X = 200
On September 25.2014 Colson Corp. sold 200.000 widgetrons for 5$ per unit.
200.000*5$=1.000.000$. Same day company was paid for 40% which is 400.000$.
The rest of the money he get paid in two equal parts on November 15.2014 and January 20.2015. So Calson Corp. was paid 300.000$ on November 15.2014 and 300.000$ on January 20.2015.