$$1stbirthdaydeposit=\mathrm{\$}500$$

$$2ndbirthdaydeposit=\mathrm{\$}500+\mathrm{\$}200=\mathrm{\$}700$$

Similarly deposit will be increased by $200 for every upcoming birthday. We have to find the deposits of all 6th birthdays.

$$\therefore 6thbirthdaydeposit=\mathrm{\$}500+\mathrm{\$}1000=\mathrm{\$}1500$$

And

$$Totalamountofmoneydeposited=\frac{500+1500}{2}\times 6=\mathrm{\$}6000$$