Jane started baby-sitting when she was 16 years old. Whenever she baby-sat for a child, that child was no more than half her age at the time. Jane is currently 32 years old, and she stopped baby-sitting 10 years ago. What is the current age of the oldest person for whom Jane could have baby-sat? Choices: A) 20 B) 21 C) 22 D) 23 E) 24
Check two extreme cases:   Jane = 16, child = 8, years ago = 32-16= 
<gadget id="calculator">32-16</gadget>
<output>16</output>
16 --&gt; child's age now= 8+16= 
<gadget id="calculator">8+16</gadget>
<output>24</output>
24;   Jane= 22, child = 11, years ago = 32-22= 
<gadget id="calculator">32-22</gadget>
<output>10</output>
10 --&gt; child's age now= 11+10= 
<gadget id="calculator">11+10</gadget>
<output>21</output>
21.   Answer: 24.
<result>E</result>
Jane started baby-sitting when she was 16 years old. Whenever she baby-sat for a child, that child was no more than half her age at the time. Jane is currently 32 years old, and she stopped baby-sitting 10 years ago. What is the current age of the oldest person for whom Jane could have baby-sat?