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?
If Ariella has $200 more in her son's saving account than Daniella has, then she has $400 + $200 = $600.
If she earns an interest of 10% in the first year, her savings account increases by 10/100 * $600 = $
<gadget id="calculator">10/100*600</gadget>
<output>60</output>
60.
In the second year, she earns the same amount of interest, which $60 + $60 = $
<gadget id="calculator">60+60</gadget>
<output>120</output>
120.
The total amount of money in Ariella's account after two years is $600 + $120 = $
<gadget id="calculator">600+120</gadget>
<output>720</output>
720.

<result>720</result>