A certain sum of money is divided among A, B and C such that A gets one-third of what B and C together get and B gets two-seventh of what A and C together get. If the amount received by A is $20 more than that received by B, find the total amount shared by A, B and C.
Choose one:  A) $320  B) $420  C) $720  D) $220  E) $200
A = 1/3 (B+$720) =&gt; $720 = 3A - B ---(1)   B = 2/7 (A+$720) =&gt; $720 = 3.5 B - A --(B)   A-B = $20   A = 20+B   (1)===&gt; $720 = 60+3B - B = 2B+60 ==&gt; 2B-$720 = -60 ---(3)   (2)===&gt; $720 = 3.5 B - B-20 = 2.5B-20==&gt;2.5B-$720 = 20---(4)   from (4) and (3) 0.5B = 80   B = $160   A= $180   $720 =540-160= 
<gadget id="calculator">540-160</gadget>
<output>380</output>
$380 Total amount= 180+160+380= 
<gadget id="calculator">180+160+380</gadget>
<output>720</output>
$720   Answer: $720
<result>C</result>
A certain sum of money is divided among A, B and C such that A gets one-third of what B and C together get and B gets two-seventh of what A and C together get. If the amount received by A is $20 more than that received by B, find the total amount shared by A, B and C.