Joan and Karl each bought a bicycle and the sum of their purchases was $800. If twice of what Joan paid was $40 more than what Karl paid, what did Joan pay for her bicycle?  Choose the correct option.
A) $280  B) $300  C) $320  D) $340  E) $360
J+K=800 so K=800-J   2J=K+40   2J=(800-J)+40   3J=840   J=280   The answer is $280.
<result>A</result>
Joan and Karl each bought a bicycle and the sum of their purchases was $800. If twice of what Joan paid was $40 more than what Karl paid, what did Joan pay for her bicycle?