Frank is 15 years younger then John. In 3 years John will be twice as old as Frank. How old will Frank be in four years? Pick one
A) 8	B) 10	C) 12	D) 14	E) 16
Frank is 15 years younger then John --&gt; F+15=J;   In 5 years John will be twice as old as Frank (in 3 year John will be J+3 years old and Frank will be F+3 years old) --&gt; J+3=2*(F+3) --&gt; (F+15)+3=2*(F+3) --&gt; F=12;   In 4 years Frank will be 12+4= 
<gadget id="calculator">12+4</gadget>
<output>16</output>
16 years old.   Answer: 16.
<result>E</result>
Frank is 15 years younger then John. In 3 years John will be twice as old as Frank. How old will Frank be in four years?