<human>:  Ariella has $200 more in her son's saving account than Daniella has in her son's savings account. Ariella's account earns her simple interest at the rate of 10% per annum. If Daniella has $400, how much money will Arialla have after two years?
<bot>: How much money does Ariella have? ** If Ariella has $200 more in her son's saving account than Daniella has, then she has $400 + $200 = $600
How much does Ariella's savings account increase by in the first year? ** If she earns an interest of 10% in the first year, her savings account increases by 10/100 * $600 = $<<10/100*600=60>>60
How much does Ariella's savings account increase by in the second year? ** In the second year, she earns the same amount of interest, which $60 + $60 = $<<60+60=120>>120
How much money will Ariella have after two years? ** The total amount of money in Ariella's account after two years is $600 + $120 = $<<600+120=720>>720
#### 720